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Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2013	Nov. 15, 2013
Document and Entity Information
Entity Registrant Name	VERACYTE, INC.
Entity Central Index Key	0001384101
Document Type	10-Q
Document Period End Date	Sep. 30, 2013
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	No
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		21,035,046
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3

CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 15,426	$ 14,002
Accounts receivable, net of allowance of $364 and $222 as of September 30, 2013 and December 31, 2012	714	569
Supplies inventory	1,392	1,050
Prepaid expenses and other current assets	2,938	710
Restricted cash		50
Total current assets	20,470	16,381
Property and equipment, net	2,826	2,446
Restricted cash	118	118
Other assets	157	122
Total assets	23,571	19,067
Current liabilities:
Accounts payable	5,604	1,888
Accrued liabilities	4,416	4,020
Deferred Genzyme co-promotion fee	2,500	2,500
Preferred stock liability		583
Total current liabilities	12,520	8,991
Long-term debt, net of discount	4,863
Deferred rent, net of current portion	250	61
Preferred stock warrant liability	252
Deferred Genzyme co-promotion fee, net of current portion	3,239	5,114
Total liabilities	21,124	14,166
Commitments and contingencies
Convertible preferred stock; $0.001 par value, 60,187,700 and 59,147,999 shares authorized at September 30, 2013 (unaudited) and December 31, 2012, respectively; 59,989,268 and 53,084,507 shares issued and outstanding at September 30, 2013 (unaudited) and December 31, 2012, respectively	79,022	63,372
Stockholders' (deficit) equity:
Common stock, $0.001 par value; 77,000,000 shares authorized; 992,578 and 667,684 shares issued and outstanding at September 30, 2013 (unaudited) and December 31, 2012, respectively	1	1
Additional paid-in capital	3,181	1,597
Accumulated deficit	(79,757)	(60,069)
Total stockholders' (deficit) equity	(76,575)	(58,471)
Total liabilities, convertible preferred stock, and stockholders' (deficit) equity	$ 23,571	$ 19,067

CONDENSED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012
CONDENSED BALANCE SHEETS
Accounts receivable, allowance (in dollars)	$ 364	$ 222
Convertible preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Convertible preferred stock, shares authorized	60,187,700	59,147,999
Convertible preferred stock, shares issued	59,989,268	53,084,507
Convertible preferred stock, shares outstanding	59,989,268	53,084,507
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	77,000,000	77,000,000
Common stock, shares issued	992,578	667,684
Common stock, shares outstanding	992,578	667,684

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS
Revenue	$ 5,594	$ 3,224	$ 15,046	$ 7,171
Operating expenses:
Cost of revenue	3,132	1,984	9,136	4,984
Research and development	2,028	1,729	5,940	4,887
Selling and marketing	3,291	2,347	8,609	5,392
General and administrative	3,244	2,103	8,772	5,721
Total operating expenses	11,695	8,163	32,457	20,984
Loss from operations	(6,101)	(4,939)	(17,411)	(13,813)
Interest expense	(126)		(131)
Other income (expense), net	(76)	1	(2,146)	1
Net loss and comprehensive loss	$ (6,303)	$ (4,938)	$ (19,688)	$ (13,812)
Net loss per common share, basic and diluted (in dollars per share)	$ (6.59)	$ (7.49)	$ (22.87)	$ (21.40)
Shares used to compute net loss per common share, basic and diluted (in shares)	955,890	659,129	860,957	645,306

CONDENSED STATEMENTS OF CASH FLOWS - USD ($)	9 Months Ended
CONDENSED STATEMENTS OF CASH FLOWS - USD ($)	Sep. 30, 2013	Sep. 30, 2012
Operating activities
Net loss	$ (19,688,000)	$ (13,812,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	717,000	526,000
Bad debt expense	184,000	144,000
Genzyme co-promotion fee amortization	(1,875,000)	(1,761,000)
Stock-based compensation	851,000	458,000
Equity-based compensation		203,000
Amortization of debt discount and issuance costs	28,000
Interest on debt balloon payment	21,000
Change in value of preferred stock liability	2,070,000
Change in value of preferred stock warrant liability	77,000
Changes in operating assets and liabilities:
Accounts receivables	(329,000)	(482,000)
Supplies inventory	(342,000)	(488,000)
Prepaid expenses and current other assets	(2,183,000)	(287,000)
Other assets	32,000	(58,000)
Accounts payable	3,813,000	747,000
Accrued liabilities and deferred rent	763,000	1,531,000
Deferred Genzyme co-promotion fee		10,000,000
Net cash used in operating activities	(15,861,000)	(3,279,000)
Investing activities
Purchases of property and equipment	(1,061,000)	(912,000)
Change in restricted cash	50,000
Net cash used in investing activities	(1,011,000)	(912,000)
Financing activities
Proceeds from the issuance of long-term debt, net of debt issuance costs	4,877,000
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs	12,945,000
Proceeds from the exercise of common stock options	474,000	66,000
Net cash provided by financing activities	18,296,000	66,000
Net increase (decrease) in cash and cash equivalents	1,424,000	(4,125,000)
Cash and cash equivalents at beginning of period	14,002,000	7,566,000
Cash and cash equivalents at end of period	$ 15,426,000	$ 3,441,000

Organization and Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2013

Organization and Summary of Significant Accounting Policies

Organization and Summary of Significant Accounting Policies

1. Organization and Summary of Significant Accounting Policies

Veracyte, Inc. (the “Company”) was incorporated in the state of Delaware on August 15, 2006 as Calderome, Inc. Calderome operated as an incubator until early 2008. On March 4, 2008, the Company changed its name to Veracyte, Inc. Veracyte is a diagnostics company pioneering the field of molecular cytology to improve patient outcomes and lower healthcare costs. The Company specifically targets diseases that often require invasive procedures for an accurate diagnosis — diseases where many healthy patients undergo costly interventions that ultimately prove unnecessary. The Company improves the accuracy of diagnosis at an earlier stage of patient care by deriving clinically actionable genomic information from cytology samples collected in an outpatient setting. The Company’s first commercial solution, the Afirma Thyroid FNA Analysis, includes as its centerpiece the Gene Expression Classifier (“GEC”). The GEC helps physicians reduce the number of unnecessary surgeries by employing a proprietary 142-gene signature to preoperatively determine whether thyroid nodules previously classified by cytopathology as indeterminate can be reclassified as benign. The Company’s operations are based in South San Francisco, California and Austin, Texas, and it operates in one segment.

Initial Public Offering

On November 4, 2013, the Company completed an initial public offering (“IPO”) of its common stock. In connection with its IPO, the Company issued and sold 5,000,000 shares of its common stock at a price to the public of $13.00 per share. As a result of the IPO, the Company received approximately $57.9 million in net proceeds, after deducting underwriting discounts and commissions of $4.6 million and estimated offering expenses of $2.5 million payable by the Company. The condensed financial statements, including share and per share amounts, do not give effect to the IPO.

Reverse Stock Split

On October 9, 2013, the Company filed a Certificate of Amendment to its Fourth Amended and Restated Certificate of Incorporation to effect a four-for-one reverse stock split of its outstanding common stock. The par value per share and the authorized number of shares of common stock and preferred stock were not adjusted as a result of the reverse stock split. All issued and outstanding shares of common stock, options to purchase common stock and related per share amounts contained in the unaudited interim condensed financial statements have been retroactively adjusted to reflect the reverse stock split for all periods presented. A proportional adjustment to the conversion ratio for each series of convertible preferred stock was also effected in connection with the reverse stock split. The unaudited interim condensed financial statements have not been retroactively adjusted to give effect to the conversion of the preferred stock into 0.25 of a share of common stock upon the closing of the IPO.

Basis of Presentation

The accompanying unaudited interim condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information in accordance with Securities and Exchange Commissions (“SEC”) instructions for interim financial reporting and assume the Company will continue as a going concern. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. The financial information for the three and nine months ended September 30, 2013 and 2012 is unaudited but includes all adjustments (consisting of only normal recurring adjustments), which the Company considers necessary for a fair presentation of the results of operations for those periods. Interim results are not necessarily indicative of results for the full fiscal year.

The unaudited interim condensed financial statements and related financial information should be read in conjunction with the audited financial statements and the related notes thereto for the year ended December 31, 2012 included in the Registration Statement on Form S-1 (No. 333-191282) filed by the Company with the SEC on September 20, 2013, as amended.

Use of Estimates

The preparation of unaudited interim condensed financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Significant items subject to such estimates include: revenue recognition; allowance for doubtful accounts; the useful lives of property and equipment; the recoverability of long-lived assets; the determination of fair value of the Company’s common stock, stock options, and preferred stock liability; income tax uncertainties, including a valuation allowance for deferred tax assets; and contingencies. The Company bases these estimates on historical and anticipated results, trends, and various other assumptions that the Company believes are reasonable under the circumstances, including assumptions as to future events. These estimates form the basis for making judgments about the carrying values of assets and liabilities and recorded revenue and expenses that are not readily apparent from other sources. Actual results could differ from those estimates and assumptions.

Concentrations of Credit Risk and Other Risks and Uncertainties

The Company’s cash and cash equivalents are deposited with two major financial institutions in the United States of America. Deposits in these institutions may exceed the amount of insurance provided on such deposits. The Company has not experienced any losses on its deposits of cash and cash equivalents.

Several of the components of the Company’s sample collection kit and test reagents are obtained from single source suppliers. If these single source suppliers fail to satisfy the Company’s requirements on a timely basis, it could suffer delays in being able to deliver Afirma, a possible loss of revenue, or incur higher costs, any of which could adversely affect its operating results.

The Company is also subject to credit risk from its accounts receivable related to its sales of Afirma. The Company generally does not perform evaluations of customers’ financial condition and generally does not require collateral. All of the Company’s accounts receivables are derived from sales of Afirma in the United States.

As of September 30, 2013 and 2012, all of the Company’s revenue is derived from the sale of Afirma. To date, Afirma has been available only to physicians in the United States. The Company’s significant third-party payers and their related revenue as a percentage of revenue were as follows:

	Nine Months Ended September 30,
	2013	2012
Medicare	33%	35%
Aetna	8%	13%
United Healthcare	17%	12%
	58%	60%

Accounts receivable from Medicare amounted to 79% and 87% of gross receivables as of September 30, 2013 and December 31, 2012, respectively. No other third-party payer represented more than 10% of the Company’s revenues or accounts receivable balances for these periods.

Cash and Cash Equivalents

Cash and cash equivalents consist of all highly liquid investments with original maturities of three months or less from the date of purchase. Cash equivalents consist primarily of amounts invested in money market accounts.

Restricted Cash

At September 30, 2013 and December 31, 2012, deposits of $118,000 and $168,000 were restricted from withdrawal and held by a bank in the form of certificates of deposit and collateral for letters of credit. The balances at September 30, 2013 and December 31, 2012 consisted of a $118,000 letter of credit related to security for the lease of office space. In addition, the balances at December 31, 2012 also included a certificate of deposit of $50,000 held as collateral for payment of the Company’s credit cards.

Allowance for Doubtful Accounts

The Company accrues an allowance for doubtful accounts against its accounts receivable based on estimates consistent with historical collection experience in relation to amounts billed. Bad debt expense is included in general and administrative expense on the Company’s statements of operations and comprehensive loss. Accounts receivable are written off against the allowance when the claims appeals process is exhausted or when there is other substantive evidence that the account will not be paid. The Company’s allowance for doubtful accounts as of September 30, 2013 and December 31, 2012 was $364,000 and $222,000, respectively. The provision for bad debt expense was $66,000 and $58,000 for the three months ended September 30, 2013 and 2012, respectively, and $184,000 and $144,000 for the nine months ended September 30, 2013 and 2012, respectively. There were $34,000 in write-offs for doubtful accounts against the allowance during the nine months ended September 30, 2013.

Supplies Inventory

Supplies inventory consists of test reagents and other consumables used in the sample collection kits and in the performance of testing services for cytopathology and for the GEC. Supplies inventory is valued at the lower of cost or market value. Cost is determined using actual costs on a first-in, first-out basis.

Internal-use Software

Capitalized software costs consist of third-party costs incurred in the application development stage to design and implement the software that is used in the GEC. Costs incurred in the development of software are capitalized and amortized over an estimated useful life of three years on a straight line basis. During the nine months ended September 30, 2013 and 2012, the Company capitalized $211,000 and $173,000 of software development costs, respectively. Capitalized software is classified as part of property and equipment, and had a net book value of $321,000 and $184,000 as of September 30, 2013 and December 31, 2012, respectively.

Bonus Accruals

The Company accrues for liabilities under discretionary employee and executive bonus plans. These estimated compensation liabilities are based on progress against corporate objectives approved by the Board of Directors, compensation levels of eligible individuals, and target bonus percentage levels. The Board of Directors and the Compensation Committee of the Board of Directors review and evaluate the performance against these objectives and ultimately determine what discretionary payments are made. At September 30, 2013 and December 31, 2012, the Company accrued $639,000 and $671,000, respectively, for liabilities associated with these employee and executive bonus plans.

Revenue Recognition

The Company’s revenue is generated from the provision of diagnostic services using its Afirma solution. Service is completed upon the delivery of test results to the prescribing physician which triggers the billing for the service. The Company recognizes revenue related to billings for commercial carriers or governmental programs subject to contractual arrangements and when there is a predictable pattern of collectability on an accrual basis, net of contractual adjustments. These contractual adjustments represent the difference between the list price (the billing rate) and the reimbursement rate set by commercial or governmental payers. Until a contract has been negotiated with a commercial carrier or governmental program, the Afirma solution may or may not be covered by these entities’ existing reimbursement policies. In addition, patients do not enter into direct agreements with us that commit them to pay any portion of the cost of the tests in the event that their insurance declines to reimburse the Company. In the absence of an agreement or other clearly enforceable legal right to demand payment, when test services are provided to patients with non-contracted insurance carriers or no insurance, the related revenue is only recognized upon the earlier of payment notification, if applicable, or cash receipt.

For all services performed, the Company considers whether or not the following revenue recognition criteria are met: persuasive evidence of an arrangement exists; delivery has occurred or services have been rendered; the fee is fixed or determinable; and collectability is reasonably assured.

Persuasive evidence of an arrangement exists and delivery is deemed to have occurred upon delivery of a patient report to the prescribing physician. The assessment of the fixed or determinable nature of the fees charged for testing performed and the collectability of those fees require significant judgment by management. Management believes that these two criteria have been met when there is contracted reimbursement coverage and/or a predictable pattern of collectability with individual third-party payers and accordingly, recognizes revenue upon delivery of the patient report. Some patients have out-of-pocket costs for amounts not covered by their insurance carrier, and the Company may bill the patient directly for these amounts in the form of co-payments and co-insurance in accordance with their insurance carrier and health plans. Some payers may not cover the GEC as ordered by the prescribing physician under their reimbursement policies. The Company pursues reimbursement from such patients on a case-by-case basis. In the absence of contracted reimbursement coverage or a predictable pattern and history of collectability, the Company believes that the fee is fixed or determinable and collectability is reasonably assured only upon receipt of third-party payer notification of payment or when cash is received and accordingly, recognizes revenue at that time.

Net Loss per Common Share

Basic net loss per common share is calculated by dividing net loss for the period by the weighted-average number of common shares outstanding during the period, without consideration of common stock equivalents. Diluted net loss per common share is computed by dividing the loss for the period by the weighted-average number of common share equivalents outstanding for the period determined using the treasury stock method. Potentially dilutive securities consisting of convertible preferred stock and options to purchase common stock are considered to be common stock equivalents and were excluded from the calculation of diluted net loss per common share because their effect would be antidilutive for all periods presented.

Recent Accounting Pronouncements

In February 2013, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income. This ASU requires reporting and disclosure about changes in accumulated other comprehensive income balances and reclassifications out of accumulated other comprehensive income. The Company adopted this guidance as of January 1, 2013 on a prospective basis and the adoption did not have a material effect on the Company’s financial statements as the Company does not have comprehensive income (loss).

In June 2011, the FASB issued authoritative guidance requiring companies to present items of net income, items of other comprehensive income and total comprehensive income in one continuous statement or two consecutive statements. This guidance eliminates the option for companies to present other comprehensive income in the statement of stockholders’ equity. The Company adopted this guidance as of January 1, 2012. As this guidance provides only presentation requirements, the adoption of this guidance did not impact the Company’s financial condition or results of operations.

In May 2011, the FASB issued authoritative guidance to achieve common fair value measurement and disclosure requirements between U.S. GAAP and International Financial Reporting Standards. This new literature amends current fair value measurement and disclosure guidance to include increased transparency around valuation inputs and investment categorization. The guidance is effective for fiscal years and interim periods beginning after December 15, 2011. The Company adopted this standard as of January 1, 2012, as reflected in Note 3 to the unaudited interim condensed financial statements.

Accrued Liabilities

9 Months Ended

Sep. 30, 2013

Accrued Liabilities

Accrued Liabilities

2. Accrued Liabilities

Accrued liabilities consist of the following (in thousands):

	September 30, 2013		December 31, 2012
Accrued compensation expenses	$	1,248	$	1,360
Accrued consulting fees	42		28
Accrued legal and professional fees	294		84
Accrued Genzyme co-promotion fees	2,322		2,175
Accrued other	510		373
Accrued liabilities	$	4,416	$	4,020

Fair Value Measurements

9 Months Ended

Sep. 30, 2013

Fair Value Measurements

Fair Value Measurements

3. Fair Value Measurements

The Company records its financial assets and liabilities at fair value. The carrying amounts of certain financial instruments of the Company, including cash and cash equivalents, prepaid expenses and other current assets, accounts payable and accrued liabilities, approximate fair value due to their relatively short maturities. The carrying value of long-term debt approximates its fair value because the interest rate approximates market rates that the Company could obtain for debt with similar terms. The accounting guidance for fair value provides a framework for measuring fair value, clarifies the definition of fair value, and expands disclosures regarding fair value measurements. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance establishes a three-tiered hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value as follows:

· Level I: Inputs which include quoted prices in active markets for identical assets and liabilities.

· Level II: Inputs other than Level I that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

· Level III: Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

The Company’s financial assets and liabilities subject to fair value measurements on a recurring basis and the level of inputs used in such measurements were as follows (in thousands):

	September 30, 2013
	Level I		Level II		Level III		Total
Financial Assets:
Money market funds	$	15,078	$	—	$	—	$	15,078
Total financial assets	$	15,078	$	—	$	—	$	15,078
Financial Liabilities:
Preferred stock warrant liability	$	—	$	—	$	252	$	252
Total financial liabilities	$	—	$	—	$	252	$	252

	December 31, 2012
	Level I		Level II		Level III		Total
Financial Assets:
Money market funds	$	12,830	$	—	$	—	$	12,830
Total financial assets	$	12,830	$	—	$	—	$	12,830
Financial Liabilities:
Preferred stock liability	$	—	$	—	$	583	$	583
Total financial liabilities	$	—	$	—	$	583	$	583

The Company’s Level III liabilities consist of a preferred stock liability and a preferred stock warrant liability (see Note 5). The following table sets forth a summary of the changes in the fair value of the Company’s Level III financial liabilities, which are measured on a recurring basis (in thousands):

Balance as of December 31, 2012	$	583
Change in fair value of preferred stock liability recorded in other income (expense), net	2,070
Settlement of preferred stock liability	(2,653		)
Fair value of preferred stock warrant liability	175
Change in fair value of preferred stock warrant liability recorded in other income (expense), net	77
Balance as of September 30, 2013	$	252

In November 2012, the Company recorded a preferred stock liability as investors received the right to purchase from the Company, on the same terms, additional shares of Series C convertible preferred stock, in a second tranche. As the investors hold a majority of the board seats, the decision to complete the second tranche was deemed to be outside the control of the Company. The preferred stock liability was valued using the option-pricing method, which resulted in an initial fair value of $0.9 million for the Company’s obligation to sell the convertible preferred stock. In June 2013, the Company settled the preferred stock liability upon completion of the sale of the second tranche of Series C convertible preferred stock. Immediately prior to settlement, the Company revalued the preferred stock liability to $2.7 million and recorded other expense of $2.1 million related to the change in value of the liability through that date. The preferred stock liability was valued using the option-pricing method with the following assumptions: 100% probability of success of the second tranche, fair value of Series C preferred stock of $2.39, a term of 0.003 years and expected volatility of 36.4%.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Debt	9 Months Ended
Debt	Sep. 30, 2013
Debt
Debt	4. Debt In June 2013, the Company entered into a loan and security agreement with a financial institution to fund its working capital and other general corporate needs. The agreement provided for term loans of up to $10.0 million in aggregate. The Company drew down $5.0 million in funds under the agreement in June 2013. The Company is required to repay the outstanding principal in 30 equal installments beginning 18 months after the date of the borrowing. The loan bears interest at a rate of 6.06% per annum. The loan carries prepayment penalties of 2.25% and 1.5% for prepayment within one and two years, respectively, of the loan origination and 0.75% thereafter. Upon execution of the loan and security agreement, the Company issued the financial institution a warrant to purchase shares of Series C convertible preferred stock at $1.89 per share (See Note 5). At the time of issuance, the aggregate fair value of the warrant for the 99,206 shares exercisable under the warrant was $175,000. The fair value of the warrant was carved out from total proceeds, resulting in a debt discount to be amortized to interest expense over 48 months, through the maturity date of the initial loan, using the effective interest rate method, and was recorded as a preferred stock warrant liability. The end of term payment of $223,000 representing 4.45% of the total outstanding principal balance will be accreted over the life of the loan as interest expense. As a result of the debt discount and the end of term payment, the effective interest rate for the loan differs from the contractual rate. Interest expense related to the amortization of the debt discount and accretion of the end of term payment was $36,000 and $38,000 for the three and nine months ended September 30, 2013, respectively. The Company may request a second term loan of up to $5.0 million on or prior to March 31, 2014. The Company’s obligations under the loan and security agreement are secured by a security interest on substantially all of its assets, excluding its intellectual property and certain other assets. The loan and security agreement contains customary conditions related to borrowing, events of default, and covenants, including covenants limiting the Company’s ability to dispose of assets, undergo a change in control, merge with or acquire other entities, incur debt, incur liens, pay dividends or other distributions to holders of its capital stock, repurchase stock and make investments, in each case subject to certain exceptions. The agreement also allows the lender to call the debt in the event there is a material adverse change in the Company’s business or financial condition. The loan and security agreement does not require that the Company comply with any financial covenants.

Convertible Preferred Stock Warrants	9 Months Ended
Convertible Preferred Stock Warrants	Sep. 30, 2013
Convertible Preferred Stock Warrants
Convertible Preferred Stock Warrants	5. Convertible Preferred Stock Warrants In June 2013, in conjunction with the execution of the loan and security agreement (Note 4), the Company issued to the lender a warrant to purchase up to 198,412 shares of Series C convertible preferred stock with an exercise price of $1.89 per share. Upon the draw down of the $5.0 million term loan, the warrant became exercisable for 99,206 shares. If the Company draws the second term loan, the remaining 99,206 shares will become exercisable under the warrant. The warrant expires at the earlier of (i) June 26, 2023 or (ii) the seventh anniversary of the Company’s initial public offering. The warrant is exercisable in cash or through a cashless exercise provision. Under the cashless exercise provision, the holder may, in lieu of payment of the exercise price in cash, surrender the warrant and receive a net amount of shares based on the fair market value of the Company’s Series C convertible preferred stock at the time of exercise of the warrant after deducting the aggregate exercise price. In the event that all outstanding shares of the Series C convertible preferred stock are converted into common stock, the warrant will be exercisable for 24,801 shares of common stock (or 49,602 shares in the aggregate if the Company draws down the second term loan), at an exercise price of $7.56 per share. The fair value of the currently exercisable portion of the warrant in the amount of $175,000 was recorded as a preferred stock warrant liability upon issuance and is subject to remeasurement at each reporting period up to the closing date of the IPO when the Series C preferred is converted into common stock. The fair value of the warrant upon issuance was calculated using the Black-Scholes option-pricing valuation model with the following assumptions: Series C preferred stock value of $2.40 per share, contractual term of 7.3 years, risk-free interest rate of 2.1%, expected volatility of 73.7%, and expected dividend yield of 0%. At September 30, 2013, the fair value of the warrant was approximately $252,000, and was calculated using the Black-Scholes option-pricing valuation model with the following assumptions: Series C preferred stock value of $3.25 per share, contractual term of 7.083 years, risk-free interest rate of 2.02%, expected volatility of 75.63%, and expected dividend yield of 0%. The change in the fair value of approximately $77,000 was reported as an expense for the three and nine months ended September 30, 2013 and is included in other income (expense), net in the unaudited interim condensed statements of operations.

Convertible Preferred Stock	9 Months Ended
Convertible Preferred Stock	Sep. 30, 2013
Convertible Preferred Stock
Convertible Preferred Stock	6. Convertible Preferred Stock In June 2013, the Company amended its Amended and Restated Certificate of Incorporation to increase the number of authorized shares of Series C convertible preferred stock from 14,000,000 to 14,852,001 and amended the Series C stock purchase agreement to increase the number of shares that may be sold in additional closings from 26,455 to a total of 1,640,212. The Company completed the second closing and two additional closings under the agreement, and received gross proceeds of $13.0 million for the issuance of an aggregate of 6,904,761 shares of Series C convertible preferred stock.

Stock Incentive Plan

9 Months Ended

Sep. 30, 2013

Stock Incentive Plan

Stock Incentive Plan

7. Stock Incentive Plan

The following table summarizes activity under the Company’s 2008 Stock Plan, including grants to non-employees and restricted stock issued (in thousands, except per share amounts):

	Shares Available for Grant		Options Outstanding		Weighted Average Exercise Price per Share		Aggregate Intrinsic Value
Balances at December 31, 2012	347,386		2,227,669		$	2.06	$	4,311
Additional options authorized	250,000		—		—
Options granted	(636,654	)	636,654		4.70
Options exercised	—		(324,892	)	1.46
Options forfeited	183,852		(183,852	)	2.69
Balances at September 30, 2013	144,584		2,355,579		$	2.81	$	21,928
Vested—September 30, 2013			1,217,163		$	2.02	$	12,290
Expected to vest—September 30, 2013			2,234,726		$	2.77	$	20,904

The aggregate intrinsic value was calculated as the difference between the exercise price of the options to purchase common stock and the estimated fair value of the Company’s common stock of $12.12 per share as of September 30, 2013.

Outstanding and exercisable stock options at September 30, 2013 are summarized as follows:

	Options Outstanding		Options Vested and Exercisable
Exercise Price	Number	Weighted-Average Remaining Contractual Life (in Years)	Number	Weighted-Average Remaining Contractual Life (in Years)
$0.08	177,750	4.89	177,750	4.89
$0.80	196,194	6.40	178,718	6.39
$2.36	430,134	7.06	328,880	7.06
$2.40	216,875	7.94	141,416	7.95
$2.68	653,952	8.53	282,438	8.51
$4.00	473,299	9.33	107,961	9.32
$6.04	198,375	9.72	—	—
$7.92	9,000	9.94	—	—
$0.08-7.92	2,355,579	8.02	1,217,163	7.28

The weighted average fair value of stock options granted was $3.73 and $1.88 per share in the nine months ended September 30, 2013 and 2012, respectively.

The weighted average fair value of stock options vested was $2.24 and $1.38 per share in the nine months ended September 30, 2013 and 2012, respectively.

The weighted average fair value of stock options exercised was $0.98 and $0.92 per share in the nine months ended September 30, 2013 and 2012, respectively. The intrinsic value of stock options exercised was $3,463,000 and $112,000 in the nine months ended September 30, 2013 and 2012, respectively.

On October 2, 2013, the Board of Directors adopted the 2013 Stock Incentive Plan which became effective immediately prior to the closing of the IPO. To the extent that any awards outstanding under the 2008 Stock Plan are subsequently forfeited or terminated for any reason before being exercised or settled, or which are subject to vesting restrictions under the 2008 Stock Plan and are subsequently forfeited, the shares of common stock reserved for issuance pursuant to such awards as of the closing of the IPO will become available for issuance under the 2013 Stock Incentive Plan. No options will be granted in the future under the 2008 Stock Plan.

Stock-based Compensation

Stock-based compensation expense recognized was as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Cost of revenue	$	10	$	5	$	23	$	21
Research and development	67		38		170		86
Selling and marketing	46		29		123		81
General and administrative	238		96		535		270
Total	$	361	$	168	$	851	$	458

As of September 30, 2013, the Company had $2.5 million of unrecognized compensation expense related to unvested stock options, which is expected to be recognized over an estimated weighted-average period of 2.94 years.

The estimated grant date fair value of employee stock options was calculated using the Black-Scholes option-pricing valuation model, based on the following assumptions:

	Three Months Ended September 30,		Nine Months Ended September 30,
	2013	2012	2013	2012
Weighted-average volatility	80.57%	84.33%	80.42 - 81.41%	83.06 - 84.33%
Weighted-average expected term (years)	6.08	6.08	5.0 - 6.08	5.0 - 6.08
Risk-free interest rate	2.11%	0.75%	0.88 – 2.11%	0.75 - 1.19%
Expected dividend yield	0%	0%	0%	0%

Stock-based compensation related to stock options granted to non-employees is recognized as the stock options are earned. The fair value of the stock options granted is calculated at each reporting date using the Black-Scholes option-pricing model with the following assumptions: expected life is the equal to the remaining contractual term of the award as of the measurement date ranging from 7.97 years to 9.18 years as of September 30, 2013 and 8.48 years to 9.44 years as of September 30, 2012; risk free rate is based on the U.S. Treasury Constant Maturity rate with a term similar to the expected life of the option at the measurement date ranging from 2.22% to 2.47% as of September 30, 2013 and 1.34% to 1.53% as of September 30, 2012; expected dividend yield of 0%; and volatilities ranging from 78.81% to 79.54% as of September 30, 2013 and 83.06% to 83.53% as of September 30, 2012.

Equity-based Compensation

The Company paid 50% of 2012 executive bonuses through the grant of stock options. The equity transaction associated with these bonuses is classified as equity-based compensation expense. The accrual for the anticipated grants was $259,000 and $0 at December 31, 2012 and September 30, 2013, respectively, and is included in accrued liabilities in the balance sheet.

In February 2013, the Company’s Board of Directors authorized the grant of 100,498 fully vested stock options at a fair value of $2.59 resulting in $259,000 in expense in the year ended December 31, 2012. The fair value of the stock options was determined using the Black-Scholes option-pricing valuation model. The grant date fair market value was $4.00 as determined by the Company’s Board of Directors, the risk free rate was 0.88%, the expected life was 5.0 years, the volatility was determined to be 81.41% and there was no dividend yield.

In February 2013, the Company granted its Chief Executive Officer an incentive stock option to purchase 12,500 shares of common stock with an exercise price of $4.00 per share and a contractual term of 10 years. The option will only vest if an initial public offering or merger occurs in 2013. The Company has not recorded any compensation expense related to this option grant as the vesting event was not deemed probable of occurring as of September 30, 2013. The option vested in full upon the closing of the Company’s IPO on November 4, 2013.

The following table summarizes equity-based compensation expense for the three and nine months ended September 30, 2013 and 2012, which were included in the unaudited interim condensed statements of operations and comprehensive loss as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Cost of revenue	$	—	$	1	$	—	$	2
Research and development	—		27		—		71
Selling and marketing	—		10		—		31
General and administrative	—		39		—		99
Total	$	—	$	77	$	—	$	203

Genzyme Co-promotion Agreement	9 Months Ended
Genzyme Co-promotion Agreement	Sep. 30, 2013
Genzyme Co-promotion Agreement
Genzyme Co-promotion Agreement	8. Genzyme Co—promotion Agreement In January 2012, the Company and Genzyme Corporation (“Genzyme”) executed a co-promotion agreement for the co-exclusive rights and license to promote and market the Company’s Afirma thyroid cancer solution in the United States and in 40 named countries. In exchange, the Company received a $10.0 million co-promotion fee from Genzyme. The Company may receive an additional $3.0 million in payments, $600,000 for each country outside of the United States in which the Company obtains marketing authorization and achieves a specified level of reimbursement, for up to five countries. Under the terms of the agreement, Genzyme will receive a percentage of cash receipts that the Company has received related to Afirma as co-promotion fees. The percentage was 50% in 2012 and decreased to 40% in January 2013 and will further decrease to 32% in March 2014 and thereafter. Genzyme will also spend up to $500,000 for qualifying clinical development activities in countries that require additional testing for approval. This obligation expires in July 2014. The Company’s agreement with Genzyme expires in January 2027 and either party may terminate the agreement at any time without cause and with six months prior notice. If the Company were to terminate the agreement without cause prior to January 2014, it would be required to repay 50% of the $10.0 million fee the Company received from Genzyme. Such percentage would be reduced to 40% of such fee if the Company were to terminate the agreement between January 2014 and January 2015, and 30% of such fee if the Company were to terminate the agreement between January 2015 and January 2016. The Company is amortizing the co-promotion fee over a four-year period, which is management’s best estimate of the life of the arrangement, in part because after that period either party may terminate the agreement without penalty. The Company amortized $625,000 in each of the three months ended September 30, 2013 and 2012, respectively, and $1.9 million and $1.8 million in the nine months ended September 30, 2013 and 2012, respectively, which are reflected as a reduction to selling and marketing expenses in the unaudited interim condensed statements of operations and comprehensive loss. The unamortized balance of the co-promotion fee is $5.7 million as of September 30, 2013. The Company incurred co-promotion expenses of $2.3 million and $1.6 million in the three months ended September 30, 2013 and 2012, respectively, and $6.0 million and $3.3 million in the nine months ended September 30, 2013 and 2012, respectively, which are reflected in selling and marketing expenses in the unaudited interim condensed statements of operations and comprehensive loss. The Company’s outstanding obligation to Genzyme totaled $6.0 million and $2.2 million at September 30, 2013 and December 31, 2012, respectively. Of the $6.0 million obligation at September 30, 2013, $3.7 million is included in accounts payable and $2.3 million is included in accrued liabilities in the Company’s condensed balance sheets. All of the $2.2 million obligation at December 31, 2012 is included in accrued liabilities in the Company’s condensed balance sheets.

Thyroid Cytology Partners	9 Months Ended
Thyroid Cytology Partners	Sep. 30, 2013
Thyroid Cytology Partners
Thyroid Cytology Partners	9. Thyroid Cytology Partners In 2010, the Company entered into an arrangement with Pathology Resource Consultants, P.A. (“PRC”) to establish and manage a specialized pathology practice to provide cytopathology testing services to the Company. There is no direct monetary compensation from the Company to PRC as a result of this arrangement. The Company’s services agreement with the specialized pathology practice, Thyroid Cytology Partners (“TCP”), is effective through December 31, 2015, unless terminated earlier, and renews annually thereafter. Under the services agreement, the Company pays TCP based on a fixed price per test schedule, which is reviewed periodically for changes in market pricing. Subsequent to December 2012, an amendment to the services agreement allows TCP to use a portion of the Company’s facility in Austin, Texas. TCP will reimburse the Company for a proportionate share of the Company’s rent and related operating expense costs for the leased facility. The Company does not have an ownership interest in or provide any form of financial or other support to TCP. The Company has concluded that TCP represents a variable interest entity and that the Company is not the primary beneficiary as it does not have the ability to direct the activities that most significantly impact TCP’s economic performance. Therefore, the Company does not consolidate TCP. All amounts paid to TCP under the services agreement are expensed as incurred. All amounts to be received from TCP will be recorded in the same period as the corresponding lease costs. TCP provided $816,000 and $491,000 in cytopathology testing and evaluation services in the three months ended September 30, 2013 and 2012, respectively, and $2,333,000 and $1,135,000 in the nine months ended September 30, 2013 and 2012, respectively. The Company also reimbursed TCP for licensure fees of $0 and $37,000 in three months ended September 30, 2013 and 2012, respectively, and $0 and $103,000 in the nine months ended September 30, 2013 and 2012, respectively. Expenses for testing and evaluation services and reimbursed professional licensure fees are included in cost of revenue in the statements of operations and comprehensive loss. The Company’s outstanding obligations to TCP were $546,000 and $458,000 as of September 30, 2013 and December 31, 2012, respectively, which were included in accounts payable in the Company’s balance sheets.

Net Loss per Common Share

9 Months Ended

Sep. 30, 2013

Net Loss per Common Share

Net Loss per Common Share

10. Net Loss per Common Share

The following table presents the calculation of basic and diluted net loss per common share for the three and nine months ended September 30, 2013 and 2012 (in thousands, except share and per share amounts):

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Net loss	$	(6,303	)	$	(4,938	)	$	(19,688	)	$	(13,812	)
Shares used to compute net loss per common share, basic and diluted	955,890			659,129			860,957			645,306
Net loss per common share, basic and diluted	$	(6.59	)	$	(7.49	)	$	(22.87	)	$	(21.40	)

The following outstanding common stock equivalents were excluded from the computation of diluted net loss per common share for the periods presented because including them would have been antidilutive:

	Nine Months Ended September 30,
	2013	2012
Convertible preferred stock (as converted)	14,997,312	11,286,998
Options to purchase common stock	2,355,579	2,179,805
Warrants to purchase convertible preferred stock (as converted)	24,801	—
Total	17,377,692	13,466,803

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2013
Income Taxes
Income Taxes	11. Income Taxes The Company did not record a provision or benefit for income taxes during the nine months ended September 30, 2013 and 2012, respectively. The Company continues to maintain a valuation allowance for its U.S. federal and state deferred tax assets. On January 2, 2013, The American Taxpayer Relief Act of 2012, or ATRA, was signed into law. Under prior law, a taxpayer was entitled to a research tax credit for qualifying amounts incurred through December 31, 2011. The ATRA extends the research credit for two years for qualified research expenditures incurred through the end of 2013. The extension of the research credit is retroactive and includes amounts incurred after 2011. At September 30, 2013, the Company had $0.7 million of unrecognized tax benefit, none of which, if recognized, would affect the effective tax rate as most of the unrecognized tax benefit is deferred tax assets currently offset by a valuation allowance. The Company has not recognized any interest and penalties related to uncertain tax positions as part of the income tax provision. The Company files annual income tax returns in the United States only. A number of years may elapse before an uncertain tax position is audited and finally resolved. While it is often difficult to predict the final outcome or the timing of resolution of any particular uncertain tax position, the Company believes that its reserves for income taxes reflect the most likely outcome. The Company adjusts these reserves, as well as the related interest, in light of changing facts and circumstances. Settlement of any particular position could require the use of cash. As of September 30, 2013, changes to the Company’s uncertain tax positions in the next twelve months that are reasonably possible are not expected to have a significant impact on the Company’s financial position or results of operations.

Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2013
Subsequent Events
Subsequent Events	12. Subsequent Events *Initial Public Offering* On November 4, 2013, the Company completed an initial public offering of its common stock. In connection with the IPO, the Company issued and sold 5,000,000 shares of its common stock at a price to the public of $13.00 per share. As a result of the IPO, the Company received approximately $57.9 million in net proceeds, after deducting underwriting discounts and commissions of $4.6 million and estimated offering expenses of $2.5 million payable by the Company. The condensed financial statements, including share and per share amounts, do not give effect to the IPO. At the closing of the IPO, 59,989,268 shares of outstanding convertible preferred stock were automatically converted into 14,997,312 shares of common stock. In addition, upon the closing of the IPO, outstanding warrants to purchase 99,206 shares of convertible preferred stock warrants were converted into warrants to purchase 24,801 shares of common stock. *Reverse Stock Split* On October 9, 2013, the Company filed a Certificate of Amendment to its Fourth Amended and Restated Certificate of Incorporation to effect a four-for-one reverse stock split of its outstanding common stock. The par value per share and the authorized number of shares of common stock and preferred stock were not adjusted as a result of the reverse stock split. All issued and outstanding shares of common stock, options to purchase common stock and related per share amounts contained in the condensed financial statements have been retroactively adjusted to reflect the reverse stock split for all periods presented. A proportional adjustment to the conversion ratio for each series of convertible preferred stock was also effected in connection with the reverse stock split. These financial statements have not been retroactively adjusted to give effect to the conversion of the preferred stock into 0.25 of a share of our common stock upon the closing of the IPO. *Restated Certificate of Incorporation* Following the conversion of each share of convertible preferred stock into shares of common stock, in connection with the IPO, the Company amended and restated its Certificate of Incorporation to delete all references to the prior series of convertible preferred stock and to give the Board of Directors the authority, without further action by the stockholders, to issue from time to time up to 5,000,000 shares of preferred stock, par value $0.001 per share, in one or more series. The Board of Directors will have the authority to establish the number of shares to be included in each series and fix the powers, preferences and rights of the shares of each wholly unissued series and any of its qualifications, limitations or restrictions. The Board of Directors will also be able to increase or decrease the number of shares of any series, but not below the number of shares of that series then outstanding, without any further vote or action by the stockholders.

Organization and Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2013

Organization and Summary of Significant Accounting Policies

Basis of Presentation

Use of Estimates

Use of Estimates

Concentrations of Credit Risk and Other Risks and Uncertainties

Concentrations of Credit Risk and Other Risks and Uncertainties

	Nine Months Ended September 30,
	2013	2012
Medicare	33%	35%
Aetna	8%	13%
United Healthcare	17%	12%
	58%	60%

Cash and Cash Equivalents

Cash and Cash Equivalents

Restricted Cash

Restricted Cash

Allowance for Doubtful Accounts

Allowance for Doubtful Accounts

Supplies Inventory

Supplies Inventory

Internal-use Software

Internal-use Software

Bonus Accruals

Bonus Accruals

Revenue Recognition

Revenue Recognition

Net Loss per Common Share

Net Loss per Common Share

Recent Accounting Pronouncements

Recent Accounting Pronouncements

Organization and Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2013

Organization and Summary of Significant Accounting Policies

Schedule of the Company's significant third-party payers and their related revenue as a percentage of revenue

	Nine Months Ended September 30,
	2013	2012
Medicare	33%	35%
Aetna	8%	13%
United Healthcare	17%	12%
	58%	60%

Accrued Liabilities (Tables)

9 Months Ended

Sep. 30, 2013

Accrued Liabilities

Schedule of accrued liabilities

Accrued liabilities consist of the following (in thousands):

	September 30, 2013		December 31, 2012
Accrued compensation expenses	$	1,248	$	1,360
Accrued consulting fees	42		28
Accrued legal and professional fees	294		84
Accrued Genzyme co-promotion fees	2,322		2,175
Accrued other	510		373
Accrued liabilities	$	4,416	$	4,020

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2013

Fair Value Measurements

Schedule of the fair value of the Company's financial assets and liabilities measured on a recurring basis

The Company’s financial assets and liabilities subject to fair value measurements on a recurring basis and the level of inputs used in such measurements were as follows (in thousands):

	September 30, 2013
	Level I		Level II		Level III		Total
Financial Assets:
Money market funds	$	15,078	$	—	$	—	$	15,078
Total financial assets	$	15,078	$	—	$	—	$	15,078
Financial Liabilities:
Preferred stock warrant liability	$	—	$	—	$	252	$	252
Total financial liabilities	$	—	$	—	$	252	$	252

	December 31, 2012
	Level I		Level II		Level III		Total
Financial Assets:
Money market funds	$	12,830	$	—	$	—	$	12,830
Total financial assets	$	12,830	$	—	$	—	$	12,830
Financial Liabilities:
Preferred stock liability	$	—	$	—	$	583	$	583
Total financial liabilities	$	—	$	—	$	583	$	583

Summary of the changes in the fair value of the Company's Level III financial liabilities, which are measured on a recurring basis

The following table sets forth a summary of the changes in the fair value of the Company’s Level III financial liabilities, which are measured on a recurring basis (in thousands):

Balance as of December 31, 2012	$	583
Change in fair value of preferred stock liability recorded in other income (expense), net	2,070
Settlement of preferred stock liability	(2,653		)
Fair value of preferred stock warrant liability	175
Change in fair value of preferred stock warrant liability recorded in other income (expense), net	77
Balance as of September 30, 2013	$	252

Stock Incentive Plan (Tables)

9 Months Ended

Sep. 30, 2013

Stock incentive plan

Summary of activity under the Company's 2008 Stock Plan, including grants to non-employees and restricted stock issued

The following table summarizes activity under the Company’s 2008 Stock Plan, including grants to non-employees and restricted stock issued (in thousands, except per share amounts):

	Shares Available for Grant		Options Outstanding		Weighted Average Exercise Price per Share		Aggregate Intrinsic Value
Balances at December 31, 2012	347,386		2,227,669		$	2.06	$	4,311
Additional options authorized	250,000		—		—
Options granted	(636,654	)	636,654		4.70
Options exercised	—		(324,892	)	1.46
Options forfeited	183,852		(183,852	)	2.69
Balances at September 30, 2013	144,584		2,355,579		$	2.81	$	21,928
Vested—September 30, 2013			1,217,163		$	2.02	$	12,290
Expected to vest—September 30, 2013			2,234,726		$	2.77	$	20,904

Summary of outstanding and exercisable stock options

Outstanding and exercisable stock options at September 30, 2013 are summarized as follows:

	Options Outstanding		Options Vested and Exercisable
Exercise Price	Number	Weighted-Average Remaining Contractual Life (in Years)	Number	Weighted-Average Remaining Contractual Life (in Years)
$0.08	177,750	4.89	177,750	4.89
$0.80	196,194	6.40	178,718	6.39
$2.36	430,134	7.06	328,880	7.06
$2.40	216,875	7.94	141,416	7.95
$2.68	653,952	8.53	282,438	8.51
$4.00	473,299	9.33	107,961	9.32
$6.04	198,375	9.72	—	—
$7.92	9,000	9.94	—	—
$0.08-7.92	2,355,579	8.02	1,217,163	7.28

Schedule of assumptions used to calculate estimated grant date fair value of employee stock options using the Black-Scholes option-pricing valuation model

	Three Months Ended September 30,		Nine Months Ended September 30,
	2013	2012	2013	2012
Weighted-average volatility	80.57%	84.33%	80.42 - 81.41%	83.06 - 84.33%
Weighted-average expected term (years)	6.08	6.08	5.0 - 6.08	5.0 - 6.08
Risk-free interest rate	2.11%	0.75%	0.88 – 2.11%	0.75 - 1.19%
Expected dividend yield	0%	0%	0%	0%

Stock-based Compensation

Stock incentive plan

Summary of share-based compensation expense

Stock-based compensation expense recognized was as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Cost of revenue	$	10	$	5	$	23	$	21
Research and development	67		38		170		86
Selling and marketing	46		29		123		81
General and administrative	238		96		535		270
Total	$	361	$	168	$	851	$	458

Equity-based Compensation

Stock incentive plan

Summary of share-based compensation expense

	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Cost of revenue	$	—	$	1	$	—	$	2
Research and development	—		27		—		71
Selling and marketing	—		10		—		31
General and administrative	—		39		—		99
Total	$	—	$	77	$	—	$	203

Net Loss per Common Share (Tables)

9 Months Ended

Sep. 30, 2013

Net Loss per Common Share

Schedule of the calculation of basic and diluted net loss per common share

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Net loss	$	(6,303	)	$	(4,938	)	$	(19,688	)	$	(13,812	)
Shares used to compute net loss per common share, basic and diluted	955,890			659,129			860,957			645,306
Net loss per common share, basic and diluted	$	(6.59	)	$	(7.49	)	$	(22.87	)	$	(21.40	)

Schedule of outstanding common stock equivalents excluded from the computation of diluted net loss per common share

	Nine Months Ended September 30,
	2013	2012
Convertible preferred stock (as converted)	14,997,312	11,286,998
Options to purchase common stock	2,355,579	2,179,805
Warrants to purchase convertible preferred stock (as converted)	24,801	—
Total	17,377,692	13,466,803

Organization and Summary of Significant Accounting Policies (Details) $ / shares in Units, $ in Millions			9 Months Ended
	Nov. 04, 2013 USD ($) $ / shares shares	Oct. 09, 2013 shares	Sep. 30, 2013 item $ / shares
Overview
Number of operating segments \| item			1
Initial Public Offering and Reverse Stock Split
Issuance price per share in IPO (in dollars per share) \| $ / shares			$ 12.12
Subsequent events
Initial Public Offering and Reverse Stock Split
Number of shares issued and sold in IPO \| shares	5,000,000
Issuance price per share in IPO (in dollars per share) \| $ / shares	$ 13.00
Net proceeds from issuance of common stock in IPO	$ 57.9
Underwriting discounts and commissions	4.6
Estimated offering expenses	$ 2.5
Reverse stock split ratio		4
Common stock issued upon conversion of each preferred stock (in shares) \| shares		0.25

Organization and Summary of Significant Accounting Policies (Details 2)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013 USD ($) item	Sep. 30, 2012 USD ($)	Sep. 30, 2013 USD ($) item	Sep. 30, 2012 USD ($)	Dec. 31, 2012 USD ($)
Concentrations of Credit Risk and Other Risks and Uncertainties
Number of major financial institutions with which the company's cash and cash equivalents are deposited \| item	2		2
Restricted Cash
Deposits	$ 118,000		$ 118,000		$ 168,000
Letter of credit serving as security for lease	118,000		118,000		118,000
Certificate of deposit					50,000
Allowance for Doubtful Accounts
Allowance for doubtful accounts	364,000		364,000		$ 222,000
Provision for bad debt expense	$ 66,000	$ 58,000	184,000	$ 144,000
Write-offs for allowance for doubtful accounts			$ 34,000
Revenue \| Revenue concentration risk
Concentrations of Credit Risk and Other Risks and Uncertainties
Concentrations of credit risk (as a percent)			58.00%	60.00%
Revenue \| Revenue concentration risk \| Medicare
Concentrations of Credit Risk and Other Risks and Uncertainties
Concentrations of credit risk (as a percent)			33.00%	35.00%
Revenue \| Revenue concentration risk \| Aetna
Concentrations of Credit Risk and Other Risks and Uncertainties
Concentrations of credit risk (as a percent)			8.00%	13.00%
Revenue \| Revenue concentration risk \| United Healthcare
Concentrations of Credit Risk and Other Risks and Uncertainties
Concentrations of credit risk (as a percent)			17.00%	12.00%
Accounts receivable \| Gross receivables concentration risk \| Medicare
Concentrations of Credit Risk and Other Risks and Uncertainties
Concentrations of credit risk (as a percent)			79.00%		87.00%

Organization and Summary of Significant Accounting Policies (Details 3) - USD ($)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Internal-use Software
Net book value	$ 2,826,000		$ 2,446,000
Capitalized software
Internal-use Software
Estimated useful life	3 years
Capitalized costs	$ 211,000	$ 173,000
Net book value	$ 321,000		$ 184,000

Organization and Summary of Significant Accounting Policies (Details 4)	9 Months Ended
	Sep. 30, 2013 USD ($) item	Dec. 31, 2012 USD ($)
Bonus Accruals
Accrued liabilities associated with employee and executive bonus plans \| $	$ 639,000	$ 671,000
Revenue Recognition
Number of specified revenue recognition criteria \| item	2

Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2013	Dec. 31, 2012
Accrued Liabilities
Accrued compensation expenses	$ 1,248	$ 1,360
Accrued consulting fees	42	28
Accrued legal and professional fees	294	84
Accrued Genzyme co-promotion fees	2,322	2,175
Accrued other	510	373
Accrued liabilities	$ 4,416	$ 4,020

Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2013	May 31, 2013	Dec. 31, 2012	Nov. 30, 2012
Preferred stock liability
Fair value measurements
Financial Liabilities		$ 2,700		$ 900
Recurring \| Level I
Fair value measurements
Financial Assets	$ 15,078		$ 12,830
Recurring \| Level I \| Money market funds
Fair value measurements
Financial Assets	15,078		12,830
Recurring \| Level III
Fair value measurements
Financial Liabilities	252		583
Recurring \| Level III \| Preferred stock liability
Fair value measurements
Financial Liabilities			583
Recurring \| Level III \| Preferred stock warrant liability
Fair value measurements
Financial Liabilities	252
Recurring \| Total
Fair value measurements
Financial Assets	15,078		12,830
Financial Liabilities	252		583
Recurring \| Total \| Preferred stock liability
Fair value measurements
Financial Liabilities			583
Recurring \| Total \| Preferred stock warrant liability
Fair value measurements
Financial Liabilities	252
Recurring \| Total \| Money market funds
Fair value measurements
Financial Assets	$ 15,078		$ 12,830

Fair Value Measurements (Details 2) $ in Thousands	9 Months Ended
Fair Value Measurements (Details 2) $ in Thousands	Sep. 30, 2013 USD ($)
Changes in the fair value of the company's Level III financial liabilities
Balance at the beginning of the period	$ 583
Change in fair value of preferred stock liability recorded in other income (expense), net	2,070
Settlement of preferred stock liability	(2,653)
Fair value of preferred stock warrant liability	175
Change in fair value of preferred stock warrant liability recorded in other income (expense), net	(77)
Balance at the end of the period	$ 252

Fair Value Measurements (Details 3) - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended
	May 31, 2013	Sep. 30, 2013	Nov. 30, 2012
Fair value measurements
Change in value of preferred stock liability		$ 2,070
Assumptions used to calculate fair value of preferred stock liability using the option-pricing method
Fair value of preferred stock (in dollars per share)		$ 12.12
Preferred stock liability
Fair value measurements
Fair value of liability	$ 2,700		$ 900
Change in value of preferred stock liability	$ 2,100
Assumptions used to calculate fair value of preferred stock liability using the option-pricing method
Probability of success of the second tranche (as a percent)	100.00%
Term	1 day
Expected volatility (as a percent)	36.40%
Series C convertible preferred stock
Assumptions used to calculate fair value of preferred stock liability using the option-pricing method
Fair value of preferred stock (in dollars per share)	$ 2.39

Debt (Details)	1 Months Ended	3 Months Ended	9 Months Ended
Debt (Details)	Jun. 30, 2013 USD ($) item $ / shares shares	Sep. 30, 2013 USD ($)	Sep. 30, 2013 USD ($)
Debt
Amount drawn down	$ 5,000,000
Amortization of debt discount and accretion			$ 28,000
Convertible Preferred Stock Warrant
Debt
Exercise price of warrants (in dollars per share) \| $ / shares	1.89
Number of shares for which warrant became exercisable \| shares	99,206
Aggregate fair value of the warrant for the shares exercisable under the warrant	$ 175,000	$ 252,000	252,000
Loan and security agreement
Debt
Maximum borrowing capacity	10,000,000
Borrowing capacity available for second term loan		5,000,000	5,000,000
Term loan
Debt
Amount drawn down	$ 5,000,000
Number of installments \| item	30
Period after which debt is repayable	18 months
Interest rate (as a percent)	6.06%
Prepayment penalties for prepayment within one year of the loan origination (as a percent)	2.25%
Prepayment penalties for prepayment within two years of the loan origination (as a percent)	1.50%
Prepayment penalties for prepayment after two years of the loan origination (as a percent)	0.75%
Amortization period of debt discount	48 months
Amount of end of term payment	$ 223,000
End of term payment as a percentage of total outstanding principal balance	4.45%
Amortization of debt discount and accretion		$ 36,000	$ 38,000

Convertible Preferred Stock Warrants (Details)	1 Months Ended	3 Months Ended	9 Months Ended
Convertible Preferred Stock Warrants (Details)	Jun. 30, 2013 USD ($) $ / shares shares	Sep. 30, 2013 USD ($) $ / shares	Sep. 30, 2013 USD ($) $ / shares
Convertible preferred stock warrant
Amount drawn down of term loan \| $	$ 5,000,000
Assumptions used to calculate fair value of warrant upon issuance using Black-Scholes option-pricing valuation model
Preferred stock value (in dollars per share) \| $ / shares		$ 12.12	$ 12.12
Amount of change in the fair value reported as an expense in other income (expense), net \| $			$ 77,000
Convertible Preferred Stock Warrant
Convertible preferred stock warrant
Number of shares of preferred stock that can be purchased by each warrant	198,412
Exercise price (in dollars per share) \| $ / shares	1.89
Number of shares for which warrant became exercisable	99,206
Number of shares for which warrant will become exercisable upon drawing the second term loan	99,206
Number of shares for which warrant will become exercisable in the event of conversion of outstanding Series C convertible preferred stock into common stock	24,801
Number of aggregate shares for which warrant will become exercisable in the event of conversion of outstanding Series C convertible preferred stock into common stock if Company draws down the second term loan	49,602
Exercise price of warrants in the event of conversion of outstanding Series C convertible preferred stock into common stock (in dollars per share) \| $ / shares	7.56
Fair value of currently exercisable portion of the warrant \| $	$ 175,000	$ 252,000	$ 252,000
Assumptions used to calculate fair value of warrant upon issuance using Black-Scholes option-pricing valuation model
Preferred stock value (in dollars per share) \| $ / shares	$ 2.40	$ 3.25	$ 3.25
Contractual term	7 years 3 months 18 days		7 years 30 days
Risk-free interest rate (as a percent)	2.10%		2.02%
Expected volatility (as a percent)	73.70%		75.63%
Expected dividend yield (as a percent)	0.00%		0.00%
Amount of change in the fair value reported as an expense in other income (expense), net \| $		$ 77,000	$ 77,000

Convertible Preferred Stock (Details) $ in Thousands	1 Months Ended	9 Months Ended
Convertible Preferred Stock (Details) $ in Thousands	Jun. 30, 2013 USD ($) item shares	Sep. 30, 2013 USD ($) shares	May 31, 2013 shares	Dec. 31, 2012 shares
Convertible preferred stock
Number of authorized shares		60,187,700		59,147,999
Gross proceeds from issuance of shares \| $		$ 12,945
Series C convertible preferred stock
Convertible preferred stock
Number of authorized shares	14,852,001		14,000,000
Number of shares that may be sold in additional closings	1,640,212		26,455
Number of additional closings \| item	2
Gross proceeds from issuance of shares \| $	$ 13,000
Number of shares issued	6,904,761

Stock Incentive Plan (Details) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2013 USD ($) $ / shares shares
Shares Available for Grant
Balances at the beginning of the period (in shares)	347,386
Additional options authorized (in shares)	250,000
Options granted (in shares)	(636,654)
Options forfeited (in shares)	183,852
Balances at the end of the period (in shares)	144,584
Options Outstanding
Balances at beginning of the period (in shares)	2,227,669
Options granted (in shares)	636,654
Options exercised (in shares)	(324,892)
Options forfeited (in shares)	(183,852)
Balances at the end of the period (in shares)	2,355,579
Vested at the end of the period (in shares)	1,217,163
Expected to vest at the end of the period (in shares)	2,234,726
Weighted Average Exercise Price per Share
Balances at beginning of the period (in dollars per share) \| $ / shares	$ 2.06
Options granted (in dollars per share) \| $ / shares	4.70
Options exercised (in dollars per share) \| $ / shares	1.46
Options forfeited (in dollars per share) \| $ / shares	2.69
Balances at the end of the period (in dollars per share) \| $ / shares	2.81
Vested at the end of the period (in dollars per share) \| $ / shares	2.02
Expected to vest at the end of the period (in dollars per share) \| $ / shares	$ 2.77
Aggregate Intrinsic Value
Balances at beginning of the period (in dollars) \| $	$ 4,311
Balances at the end of the period (in dollars) \| $	21,928
Vested at the end of the period (in dollars) \| $	12,290
Expected to vest at the end of the period (in dollars) \| $	$ 20,904
Additions disclosures
Estimated fair value common stock (in dollars per share) \| $ / shares	$ 12.12

Stock Incentive Plan (Details 2)	9 Months Ended
Stock Incentive Plan (Details 2)	Sep. 30, 2013 $ / shares shares
$0.08
Outstanding and exercisable stock options
Exercise price (in dollars per share) \| $ / shares	$ 0.08
Options Outstanding, Number	177,750
Options Outstanding, Weighted-Average Remaining Contractual Life	4 years 10 months 20 days
Options Vested and Exercisable, Number	177,750
Options Vested and Exercisable, Weighted-Average Remaining Contractual Life	4 years 10 months 20 days
$0.80
Outstanding and exercisable stock options
Exercise price (in dollars per share) \| $ / shares	$ 0.80
Options Outstanding, Number	196,194
Options Outstanding, Weighted-Average Remaining Contractual Life	6 years 4 months 24 days
Options Vested and Exercisable, Number	178,718
Options Vested and Exercisable, Weighted-Average Remaining Contractual Life	6 years 4 months 20 days
$2.36
Outstanding and exercisable stock options
Exercise price (in dollars per share) \| $ / shares	$ 2.36
Options Outstanding, Number	430,134
Options Outstanding, Weighted-Average Remaining Contractual Life	7 years 22 days
Options Vested and Exercisable, Number	328,880
Options Vested and Exercisable, Weighted-Average Remaining Contractual Life	7 years 22 days
$2.40
Outstanding and exercisable stock options
Exercise price (in dollars per share) \| $ / shares	$ 2.40
Options Outstanding, Number	216,875
Options Outstanding, Weighted-Average Remaining Contractual Life	7 years 11 months 8 days
Options Vested and Exercisable, Number	141,416
Options Vested and Exercisable, Weighted-Average Remaining Contractual Life	7 years 11 months 12 days
$2.68
Outstanding and exercisable stock options
Exercise price (in dollars per share) \| $ / shares	$ 2.68
Options Outstanding, Number	653,952
Options Outstanding, Weighted-Average Remaining Contractual Life	8 years 6 months 11 days
Options Vested and Exercisable, Number	282,438
Options Vested and Exercisable, Weighted-Average Remaining Contractual Life	8 years 6 months 4 days
$4.00
Outstanding and exercisable stock options
Exercise price (in dollars per share) \| $ / shares	$ 4.00
Options Outstanding, Number	473,299
Options Outstanding, Weighted-Average Remaining Contractual Life	9 years 3 months 29 days
Options Vested and Exercisable, Number	107,961
Options Vested and Exercisable, Weighted-Average Remaining Contractual Life	9 years 3 months 25 days
$6.04
Outstanding and exercisable stock options
Exercise price (in dollars per share) \| $ / shares	$ 6.04
Options Outstanding, Number	198,375
Options Outstanding, Weighted-Average Remaining Contractual Life	9 years 8 months 19 days
$7.92
Outstanding and exercisable stock options
Exercise price (in dollars per share) \| $ / shares	$ 7.92
Options Outstanding, Number	9,000
Options Outstanding, Weighted-Average Remaining Contractual Life	9 years 11 months 8 days
$0.08-7.92
Outstanding and exercisable stock options
Exercise price, low end of range (in dollars per share) \| $ / shares	$ 0.08
Exercise price, high end of range (in dollars per share) \| $ / shares	$ 7.92
Options Outstanding, Number	2,355,579
Options Outstanding, Weighted-Average Remaining Contractual Life	8 years 7 days
Options Vested and Exercisable, Number	1,217,163
Options Vested and Exercisable, Weighted-Average Remaining Contractual Life	7 years 3 months 11 days

Stock Incentive Plan (Details 3) - USD ($)	9 Months Ended
Stock Incentive Plan (Details 3) - USD ($)	Sep. 30, 2013	Sep. 30, 2012
Stock Incentive Plan
Weighted average fair value of stock options granted (in dollars per share)	$ 3.73	$ 1.88
Weighted average fair value of stock options vested (in dollars per share)	2.24	1.38
Weighted average fair value of stock options exercised (in dollars per share)	$ 0.98	$ 0.92
Intrinsic value of stock options exercised (in dollars)	$ 3,463,000	$ 112,000

Stock Incentive Plan (Details 4) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Stock Incentive Plan (Details 4) - USD ($) $ in Thousands	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Stock-based Compensation
Stock-based compensation
Share-based compensation expense	$ 361	$ 168	$ 851	$ 458
Unrecognized compensation expense	2,500		$ 2,500
Period over which unrecognized compensation expense expected to be recognized			2 years 11 months 8 days
Stock-based Compensation \| Cost of revenue
Stock-based compensation
Share-based compensation expense	10	5	$ 23	21
Stock-based Compensation \| Research and development
Stock-based compensation
Share-based compensation expense	67	38	170	86
Stock-based Compensation \| Selling and marketing
Stock-based compensation
Share-based compensation expense	46	29	123	81
Stock-based Compensation \| General and administrative
Stock-based compensation
Share-based compensation expense	$ 238	96	$ 535	270
Equity-based Compensation
Stock-based compensation
Share-based compensation expense		77		203
Equity-based Compensation \| Cost of revenue
Stock-based compensation
Share-based compensation expense		1		2
Equity-based Compensation \| Research and development
Stock-based compensation
Share-based compensation expense		27		71
Equity-based Compensation \| Selling and marketing
Stock-based compensation
Share-based compensation expense		10		31
Equity-based Compensation \| General and administrative
Stock-based compensation
Share-based compensation expense		$ 39		$ 99

Stock Incentive Plan (Details 5) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
Stock Incentive Plan (Details 5) - USD ($)	Feb. 28, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Grant date fair market value (in dollars per share)		$ 12.12		$ 12.12
Anticipated grants accrual		$ 1,248,000		$ 1,248,000		$ 1,360,000
Fair value (in dollars per share)				$ 2.24	$ 1.38
Options granted (in shares)				636,654,000
Exercise price (in dollars per share)				$ 4.70
Stock-based Compensation, employee
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average volatility, low end of range (as a percent)				80.42%	83.06%
Weighted-average volatility, high end of range (as a percent)				81.41%	84.33%
Weighted-average volatility (as a percent)		80.57%	84.33%
Weighted-average expected term		6 years 29 days	6 years 29 days
Risk-free interest rate, low end of range (as a percent)				0.88%	0.75%
Risk-free interest rate, high end of range (as a percent)				2.11%	1.19%
Risk-free interest rate (as a percent)		2.11%	0.75%
Expected dividend yield (as a percent)		0.00%	0.00%	0.00%	0.00%
Stock-based Compensation, employee \| Minimum
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average expected term				5 years	5 years
Stock-based Compensation, employee \| Maximum
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average expected term				6 years 29 days	6 years 29 days
Stock-based Compensation, non-employee
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average volatility, low end of range (as a percent)				78.81%	83.06%
Weighted-average volatility, high end of range (as a percent)				79.54%	83.53%
Risk-free interest rate, low end of range (as a percent)				2.22%	1.34%
Risk-free interest rate, high end of range (as a percent)				2.47%	1.53%
Expected dividend yield (as a percent)				0.00%	0.00%
Stock-based Compensation, non-employee \| Minimum
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average expected term				7 years 11 months 19 days	8 years 5 months 23 days
Stock-based Compensation, non-employee \| Maximum
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Weighted-average expected term				9 years 2 months 5 days	9 years 5 months 8 days
Equity-based Compensation, executive bonus
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Grant date fair market value (in dollars per share)	$ 4.00
Weighted-average volatility (as a percent)	81.41%
Weighted-average expected term	5 years
Risk-free interest rate (as a percent)	0.88%
Expected dividend yield (as a percent)	0.00%
Percentage of executive bonus to be paid through grant of stock options						50.00%
Anticipated grants accrual		$ 0		$ 0		$ 259,000
Fair value (in dollars per share)	$ 2.59
Share-based compensation expense						$ 259,000
Options granted (in shares)	100,498
Equity-based Compensation, incentive stock options \| Chief Executive Officer
Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model
Options granted (in shares)	12,500
Exercise price (in dollars per share)	$ 4.00
Contractual term	10 years

Genzyme Co-promotion Agreement (Details)	1 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended
Genzyme Co-promotion Agreement (Details)	Jan. 31, 2013	Jan. 31, 2012 USD ($) item	Sep. 30, 2013 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2013 USD ($) item	Sep. 30, 2012 USD ($)	Dec. 31, 2012 USD ($)
Genzyme Co-promotion Agreement
Co-promotion fee received from Genzyme						$ 10,000,000
Amortization of co-promotion fee					$ 1,875,000	1,761,000
Co-promotion agreement
Genzyme Co-promotion Agreement
Number of countries outside United States in which marketing authorization is obtained \| item		40
Co-promotion fee received from Genzyme		$ 10,000,000
Additional payments that may be received					3,000,000
Additional payments that may be received for each country outside of the United States in which the company obtains marketing authorization and achieves a specified level of reimbursement					$ 600,000
Number of countries outside United States for which additional payments may be received \| item					5
Prior notice period for termination of agreement					6 months
Amortization period of co-promotion fee					4 years
Amortization of co-promotion fee			$ 625,000	$ 625,000	$ 1,900,000	1,800,000
Unamortized balance of the co-promotion fee			5,700,000		5,700,000
Co-promotion expenses			2,300,000	$ 1,600,000	6,000,000	$ 3,300,000
Outstanding obligation to Genzyme			6,000,000		6,000,000		$ 2,200,000
Co-promotion agreement \| Accounts payable
Genzyme Co-promotion Agreement
Outstanding obligation to Genzyme			3,700,000		3,700,000
Co-promotion agreement \| Accrued liabilities
Genzyme Co-promotion Agreement
Outstanding obligation to Genzyme			$ 2,300,000		$ 2,300,000		$ 2,200,000
Co-promotion agreement \| Genzyme
Genzyme Co-promotion Agreement
Percentage of cash receipts of co-promotion fees received by co-promoter	40.00%						50.00%
Percentage of cash receipts of co-promotion fees received by co-promoter for remaining periods					32.00%
Maximum amount to be spent by co-promoter for qualifying clinical development activities in countries that require additional testing					$ 500,000
Percentage of co-promotion fee required to be repaid if agreement terminated prior to January 2014					50.00%
Percentage of co-promotion fee required to be repaid if agreement terminated between January 2014 and January 2015					40.00%
Percentage of co-promotion fee required to be repaid if agreement terminated between January 2015 and January 2016					30.00%

Thyroid Cytology Partners (Details) - USD ($)	3 Months Ended		9 Months Ended
Thyroid Cytology Partners (Details) - USD ($)	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Thyroid Cytology Partners
Outstanding obligations	$ 5,604,000		$ 5,604,000		$ 1,888,000
Thyroid Cytology Partners
Thyroid Cytology Partners
Expenses for cytopathology testing and evaluation services	816,000	$ 491,000	2,333,000	$ 1,135,000
Reimbursed professional licensure fees	0	$ 37,000	0	$ 103,000
Outstanding obligations	$ 546,000		$ 546,000		$ 458,000

Net Loss per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Calculation of basic and diluted net loss per common share
Net loss	$ (6,303)	$ (4,938)	$ (19,688)	$ (13,812)
Shares used to compute net loss per common share, basic and diluted (in shares)	955,890	659,129	860,957	645,306
Net loss per common share, basic and diluted (in dollars per share)	$ (6.59)	$ (7.49)	$ (22.87)	$ (21.40)
Outstanding common stock equivalents excluded from the computation of diluted net loss per common share
Outstanding common stock equivalents (in shares)			17,377,692	13,466,803
Convertible preferred stock (as converted)
Outstanding common stock equivalents excluded from the computation of diluted net loss per common share
Outstanding common stock equivalents (in shares)			14,997,312	11,286,998
Options to purchase common stock
Outstanding common stock equivalents excluded from the computation of diluted net loss per common share
Outstanding common stock equivalents (in shares)			2,355,579	2,179,805
Warrants to purchase convertible preferred stock (as converted)
Outstanding common stock equivalents excluded from the computation of diluted net loss per common share
Outstanding common stock equivalents (in shares)			24,801

Income Taxes (Details) - USD ($) $ in Millions	Jan. 02, 2013	Sep. 30, 2013
Income Taxes
Period for which research tax credit extended for qualified research expenditures incurred through the end of 2013	2 years
Unrecognized tax benefit		$ 0.7
Unrecognized tax benefits, which if recognized, would affect the effective tax rate		$ 0.0

Subsequent Events (Details) $ / shares in Units, $ in Millions	Nov. 04, 2013 USD ($) item $ / shares shares	Oct. 09, 2013 shares	Sep. 30, 2013 $ / shares
Subsequent Events
Issuance price per share in IPO (in dollars per share) \| $ / shares			$ 12.12
Subsequent Events
Subsequent Events
Number of shares issued and sold in IPO	5,000,000
Issuance price per share in IPO (in dollars per share) \| $ / shares	$ 13.00
Net proceeds from issuance of common stock in IPO \| $	$ 57.9
Underwriting discounts and commissions \| $	4.6
Estimated offering expenses \| $	$ 2.5
Convertible preferred stock converted to common stock (in shares)	59,989,268
Common stock issued on automatic conversion of outstanding convertible preferred stock (in shares)	14,997,312
Preferred stock warrants converted (in shares)	99,206
Warrants issued to purchase common stock upon conversion of preferred stock warrants (in shares)	24,801
Reverse stock split ratio		4
Common stock issued upon conversion of each preferred stock (in shares)		0.25
Number of shares of preferred stock authorized	5,000,000
Preferred stock, par value (in dollars per share) \| $ / shares	$ 0.001
Subsequent Events \| Maximum
Subsequent Events
Number of series in which preferred stock may be issued \| item	1