Accounting Policies [Abstract] Concentration Risk [Table] Concentration Risk [Table] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Revenue Sales Revenue Gross [Member] Revenue from sale of goods and services rendered, in the normal course of business, before deducting sales returns and allowances, and sales discounts, when it serves as a benchmark in a concentration of risk calculation. Accounts receivable Accounts Receivable [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Revenue concentration risk Customer Concentration Risk [Member] Gross receivables concentration risk Credit Concentration Risk [Member] Health Care Organization, Revenue Sources [Axis] Health Care Organization, Revenue Sources [Axis] Health Care Organization, Revenue Sources [Domain] Health Care Organization, Revenue Sources [Domain] Medicare Medicare [Member] Represents information pertaining to Medicare, a significant third-party payer. UnitedHealthcare United Healthcare [Member] Represents information pertaining to United Healthcare, a significant third-party payer. Aetna Aetna [Member] Represents information pertaining to Aetna, a significant third-party payer. Concentrations of Credit Risk and Other Risks and Uncertainties Concentration Risk [Line Items] Concentrations of Credit Risk and Other Risks and Uncertainties Concentrations of Credit Risk and Other Risks and Uncertainties No definition available. Number of major financial institutions with which the company's cash and cash equivalents are deposited Number of Major Financial Institutions with which Cash and Cash Equivalents Deposited Represents the number of major financial institutions, with which cash and cash equivalents are deposited by the entity. Concentrations of credit risk (as a percent) Concentration Risk, Percentage Thyroid Cytopathology Partners Thyroid Cytopathology Partners Long-term Contracts or Programs Disclosure [Text Block] Organization and Description of Business Business Description and Basis of Presentation [Text Block] Subsequent Events [Abstract] Subsequent Event [Table] Subsequent Event [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Common Stock Common Stock [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Sale of Stock [Axis] Sale of Stock [Axis] Sale of Stock [Domain] Sale of Stock [Domain] Over-Allotment Option Over-Allotment Option [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Sale of stock, number of shares issued in transaction Sale of Stock, Number of Shares Issued in Transaction Sale of stock, price per share (in usd per share) Sale of Stock, Price Per Share Sale of stock, consideration received on transaction, gross Sale of Stock, Consideration Received on Transaction, Gross Sale of Stock, Consideration Received on Transaction, Gross Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Line of Credit Line of Credit [Member] Term Loans Term Loan [Member] Represents the term loans under the loan and security agreement. Lender Name [Axis] Lender Name [Axis] Line of Credit Facility, Lender [Domain] Line of Credit Facility, Lender [Domain] Visium Visium [Member] Represents information pertaining to Visium Healthcare Partners, LP Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Initial Term Loan Initial Term Loan [Member] Represents the initial term loan. Second Term Loan Second Term Loan [Member] Represents the second term loan. Range [Axis] Range [Axis] Range [Domain] Range [Domain] Maximum Maximum [Member] Debt Debt Instrument [Line Items] Number of term loans Number Of Term Loans Represents the number of term loans available to the Company. Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Drawn down initial term loan Proceeds from Lines of Credit Repayment of long-term debt Repayments of Long-term Debt Interest rate (as a percent) Debt Instrument, Interest Rate, Stated Percentage Number of installments Debt Instrument Number of Installments Represents the number of installments for payment of the debt. Term of debt with equal quarterly installments Term Of Debt With Equal Quarterly Installments Represents the term of debt with equal quarterly installments. Rate for which Company may elect to pay interest in cash (as a percent) Debt Instrument Fixed Rate Percentage Paid In Cash Rate for which Company may elect to pay interest in cash. Remaining percentage for which interest is paid-in-kind Debt Instrument Interest Paid-In-Kind Percentage Percentage of interest rate for which interest is paid-in-kind by adding paid-in-kind interest to the outstanding principal amounts of the Term Loans. Paid-in-kind interest Paid-in-Kind Interest Prepayment allowed Debt Instrument Minimum Prepayment Allowed Amount of prepayment allowed under the current agreement. Whole multiple in excess of minimum prepayment Debt Instrument Prepayment Amount Excess Multiple The whole multiple for which payments must be made in excess of minimum prepayment. Prepayment premium for prepayment made on or prior to March 31, 2018 (as a percent) Debt Instrument Penalty Percentage On Prepayment Period One Represents the percentage of prepayment premium for prepayment made on or prior to March 31, 2018. Prepayment premium for prepayment made after March 31, 2018 and on or prior to March 31, 2019 (as a percent) Debt Instrument Penalty Percentage On Prepayment Period Two Represents the percentage of prepayment premium for prepayment after March 31, 2018 and on or prior to March 31, 2019. Prepayment premium for prepayment made after March 31, 2019 and on or prior to March 31, 2020 (as a percent) Debt Instrument Penalty Percentage On Prepayment Period Three Represents the percentage of prepayment premium for prepayment after March 31, 2019 and on or prior to March 31, 2020. Prepayment premium for prepayment made after March 31, 2020 and on or prior to March 31, 2021 (as a percent) Debt Instrument Penalty Percentage On Prepayment Period Four Represents the percentage of prepayment premium for prepayment after March 31, 2020 and on or prior to March 31, 2021. Prepayment premium for prepayment made after March 31, 2021 (as a percent) Debt Instrument Penalty Percentage On Prepayment Period Five Represents the percentage of prepayment premium for prepayment after March 31, 2021. Period for which lender has rights to participate in equity financings Debt Instrument Period For Which Rights Equity Financings The period for which the lender has the right to participate in certain future equity financings of the Company. Maximum amount allowed to participate in future equity financings Debt Instrument Future Equity Financings Amount The amount for which lender can participate in future equity financings. Debt principal Debt Instrument, Face Amount Unamortized deferred debt issuance costs Debt Instrument, Unamortized Discount Net debt obligation Long-term Debt Future principal payments Long-term Debt, Fiscal Year Maturity [Abstract] 2020 Long-term Debt, Maturities, Repayments of Principal in Year Five Thereafter Long-term Debt, Maturities, Repayments of Principal after Year Five Total Long-term Debt, Gross Amount drawn down Debt Instrument, Increase (Decrease), Net Interest Expense, Debt [Abstract] Interest Expense, Debt [Abstract] Nominal interest Interest Expense, Debt, Excluding Amortization Amortization and write-off of debt discount and debt issuance costs Amortization of Debt Discount (Premium) Prepayment penalty Prepayment Penalty Prepayment penalty. End-of-term payment interest Debt instrument end of term payment interest amount Represents the amount of interest end of term payment of debt. Total Interest Expense, Debt Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Payables and Accruals [Abstract] Accrued compensation expenses Employee-related Liabilities, Current Accrued Genzyme co-promotion fees Accrued Marketing Costs, Current Accrued other Other Accrued Liabilities, Current Total accrued liabilities Accrued Liabilities, Current Equity [Abstract] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Shares of common stock subject to outstanding options Employee And Non Employee Stock Option [Member] An arrangement whereby an employee or non-employee is entitled to receive in the future, subject to vesting and other restrictions, number of shares in the entity at a specified price, as defined in the agreement. ESPP Employee Stock [Member] Class of Stock [Line Items] Class of Stock [Line Items] Common Stock Common Stock [Abstract] No definition available. Options issued and outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Shares available for issuance Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Total number of shares reserved for issuance Common Stock, Capital Shares Reserved for Future Issuance Earnings Per Share [Abstract] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Employee stock purchase plan Employee Stock Option [Member] Outstanding shares of common stock equivalents that have been excluded from diluted net loss per common share Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Total common stock equivalents (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Shares Available for Grant Share Based Compensation Arrangement by Share Based Payment Award Number of Shares Available for Grant [Roll Forward] Balance at the beginning of the period (in shares) Additional options authorized (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Canceled (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Balance at the end of the period (in shares) Stock Options Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Balance at beginning of the period (in shares) Granted (in shares) Canceled (in shares) Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period 1 The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan. Exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Balance at the end of the period (in shares) Options vested and exercisable at the end of the period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Options vested and expected to vest at the end of the period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Balance at beginning of the period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Granted (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Canceled (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Exercised (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Balance at the end of the period (in dollars per share) Options vested and exercisable at the end of the period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Options vested and expected to vest at the end of the period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Weighted Average Remaining Contractual Life Share Based Compensation Arrangement by Share Based Payment Award Options Weighted Average Remaining Contractual Life [Abstract] Balance (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Options vested and exercisable at the end of the period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Options vested and expected to vest at the end of the period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Aggregate Intrinsic Value Share Based Compensation Arrangement by Share Based Payment Award Options Aggregate Intrinsic Value [Abstract] Balance at the beginning of the period (in dollars) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Balance at the end of the period (in dollars) Options vested and exercisable at the end of the period (in dollars) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Options vested and expected to vest at the end of the period (in dollars) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Schedule of accrued liabilities Schedule of Accrued Liabilities [Table Text Block] Net Loss Per Common Share Earnings Per Share [Text Block] Statement of Financial Position [Abstract] Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized Preferred Stock, Shares Authorized Preferred stock, shares issued Preferred Stock, Shares Issued Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Common stock, shares outstanding Common Stock, Shares, Outstanding Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Concentrations of Credit Risk and Other Risks and Uncertainties Concentrations of Credit and Other Risks and Uncertainties [Policy Text Block] Disclosure of accounting policy for concentrations of credit risk and other risks and uncertainties. Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Fair Value of Financial Instruments Fair Value of Financial Instruments, Policy [Policy Text Block] Revenue Recognition Revenue Recognition, Policy [Policy Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Schedule of future minimum lease payments under non-cancelable operating leases Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Stock Incentive Plans Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Income Statement [Abstract] Revenue Revenue, Net Operating expenses: Operating Expenses [Abstract] Cost of revenue Cost of Revenue Research and development Research and Development Expense Selling and marketing Selling and Marketing Expense General and administrative General and Administrative Expense Intangible asset amortization Amortization of Intangible Assets Total operating expenses Costs and Expenses Loss from operations Operating Income (Loss) Interest expense Interest Expense Other income, net Other Nonoperating Income (Expense) Net loss Net Income (Loss) Available to Common Stockholders, Basic Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Net loss per common share, basic and diluted (in usd per share) Earnings Per Share, Basic and Diluted Shares used to compute net loss per common share, basic and diluted Weighted Average Number of Shares Outstanding, Basic and Diluted Schedule of reserved shares of common stock for issuance Schedule of Common Stock Capital Shares Reserved for Future Issuance [Table Text Block] Tabular disclosure of number of common shares reserved for future issuance. Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Genzyme Co-promotion Agreement Schedule of Collaborative Arrangements and Non-collaborative Arrangement Transactions [Table] Schedule of Collaborative Arrangements and Non-collaborative Arrangement Transactions [Table] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Selling and marketing Selling and Marketing Expense [Member] Type of Arrangement and Non-arrangement Transactions [Axis] Type of Arrangement and Non-arrangement Transactions [Axis] Arrangements and Non-arrangement Transactions [Domain] Arrangements and Non-arrangement Transactions [Domain] Co-promotion agreement Collaborative Arrangement, Co-promotion [Member] Afirma thyroid diagnostic solution co-promotion agreement Collaborative Arrangement Copromotion Afirma Thyroid Diagnostic Solution [Member] Contractual arrangement involving the promotion the Company's Afirma thyroid diagnostic solution in which both the entity and its partner: (i) actively participate in the joint operating activity and (ii) are exposed to significant risks and rewards that depend on the commercial success of the joint operating activity. Ex-U.S. Co-Promotion Agreement Collaborative Arrangement Copromotion Afirma Gec [Member] Contractual arrangement involving the promotion of Afirma GEC in countries other than the United States in which both the entity and its partner: (i) actively participate in the joint operating activity and (ii) are exposed to significant risks and rewards that depend on the commercial success of the joint operating activity. Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Genzyme Genzyme Corporation [Member] Represents information pertaining to Genzyme Corporation, a co-promoter. Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Accrued liabilities Accrued Liabilities [Member] Genzyme Co-promotion Agreement Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] Number of countries outside United States for exclusive promotion under the agreement Collaborative Arrangement Number of Countries Outside United States in which Marketing Authorization is Obtained Represents the number of countries outside United States in which marketing authorization is obtained under the agreement. Co-promotion fee received from Genzyme Increase (Decrease) in Deferred Revenue Co-promotion fees as a percentage of cash receipts Collaborative Arrangement Co-promotion fees percentage of cash receipts Represents the co-promotion fees paid to co-promoter as a percentage of cash receipts under the agreement. Co-promotion fees as a percentage of cash receipts for remaining periods Collaborative Arrangement Co-promotion fees percentage of cash receipts remaining periods Represents the co-promotion fees paid to co-promoter as a percentage of cash receipts for the remaining periods under the agreement. Straight-line amortization period of co-promotion fee Collaborative Arrangement Co Promotion Fee Amortization Period Represents the amortization period of co-promotion fee. Co-promotion fee paid as a percentage of net revenue Collaborative Arrangement Co-promotion Fees Percentage of Net Revenue Represents the co-promotion fees paid to co-promoter as a percentage of net revenue under the agreement. Period of agreement Collaborative Arrangement, Term Represents the term of the co-promotion agreement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Co-promotion expenses Collaborative Arrangement Co Promotion Expenses Represents the amount of co-promotion expenses incurred under the agreement. Genzyme co-promotion fee amortization Recognition of Deferred Revenue Subsequent Event Subsequent Events [Text Block] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Recurring Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level I Fair Value, Inputs, Level 1 [Member] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Money market funds Money Market Funds [Member] Fair value measurements Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Financial Assets Assets, Fair Value Disclosure Debt Debt Disclosure [Text Block] Unrecognized tax benefit Unrecognized Tax Benefits Interest expense or penalties related to unrecognized tax benefits Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense Genzyme Co-promotion Agreement Collaborative Arrangement Disclosure [Text Block] Statement of Cash Flows [Abstract] Operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Net loss Adjustments to reconcile net loss to net cash used in operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Bad debt expense Provision for Doubtful Accounts Loss on disposal of property and equipment Gain (Loss) on Disposition of Property Plant Equipment Genzyme co-promotion fee amortization Stock-based compensation Share-based Compensation Conversion of accrued interest to long-term debt Amortization and write-off of debt discount and issuance costs Amortization of Debt Issuance Costs and Discounts Interest on debt balloon payment and prepayment penalty Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable Increase (Decrease) in Accounts Receivable Supplies inventory Increase (Decrease) in Inventories Prepaid expenses and current other assets Increase (Decrease) in Prepaid Expense and Other Assets Other assets Increase (Decrease) in Other Noncurrent Assets Accounts payable Increase (Decrease) in Accounts Payable Accrued liabilities and deferred rent Increase (Decrease) in Accrued Liabilities and Deferred Rent The increase (decrease) during the reporting period in the amount of expenses incurred but not yet paid and deferred rent. Net cash used in operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations Investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Change in restricted cash Increase (Decrease) in Restricted Cash Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations Financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Proceeds from the issuance of long-term debt, net of debt issuance costs Proceeds from Issuance of Long-term Debt Proceeds from the issuance of common stock in a private placement, net of costs Proceeds from Issuance of Private Placement Payment of deferred stock offering costs Payments of Stock Issuance Costs Payment of long-term debt Payment of end-of-term debt obligation and prepayment penalty Payment of End of Term Obligation The cash outflow for the payment of the end-of-term obligation and prepayment penalty. Proceeds from the exercise of common stock options and employee stock purchases Proceeds from Stock Options Exercised Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net (decrease) increase in cash and cash equivalents Net Cash Provided by (Used in) Continuing Operations Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of period Supplementary cash flow information of non-cash investing and financing activities: Supplemental Cash Flow Information [Abstract] Purchases of property and equipment included in accounts payable and accrued liabilities Capital Expenditures Incurred But Not Yet Paid Net Future cash outflow (inflow) to pay for purchases of fixed assets that have occurred. Unpaid deferred stock offering Deferred Stock Offering Costs Amount of deferred stock offering costs not yet paid. Schedule of net debt obligation Schedule of Debt [Table Text Block] Schedule of future principal payments under the Credit agreement Contractual Obligation, Fiscal Year Maturity Schedule [Table Text Block] Schedule of interest expense on debt Interest Income and Interest Expense Disclosure [Table Text Block] Assets Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Accounts receivable Accounts Receivable, Net, Current Supplies inventory Inventory, Net Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Restricted cash Restricted Cash and Cash Equivalents, Current Total current assets Assets, Current Property and equipment, net Property, Plant and Equipment, Net Finite-lived intangible assets, net Finite-Lived Intangible Assets, Net Goodwill Goodwill Restricted cash Restricted Cash and Cash Equivalents, Noncurrent Other assets Other Assets, Noncurrent Total assets Assets Liabilities and Stockholders’ Equity Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued liabilities Deferred Genzyme co-promotion fee Deferred Revenue, Current Total current liabilities Liabilities, Current Long-term debt Long-term Debt, Excluding Current Maturities Deferred rent, net of current portion Deferred Rent Credit, Noncurrent Total liabilities Liabilities Commitments and contingencies Commitments and Contingencies Stockholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, $0.001 par value; 5,000,000 shares authorized, no shares issued and outstanding as of September 30, 2016 and December 31, 2015 Preferred Stock, Value, Issued Common stock, $0.001 par value; 125,000,000 shares authorized, 27,940,161 and 27,685,291 shares issued and outstanding as of September 30, 2016 and December 31, 2015, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Accumulated deficit Retained Earnings (Accumulated Deficit) Total stockholders’ equity Stockholders' Equity Attributable to Parent Total liabilities and stockholders’ equity Liabilities and Equity Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Stock-based Compensation Employee And Non Employee Stock Option Excluding Bonus Compensation [Member] An arrangement whereby an employee or non-employee is entitled to receive in the future, subject to vesting and other restrictions, a number of shares in the entity at a specified price, as defined in the agreement, excluding options granted as bonus related compensation. Stock-based Compensation, employees Employee Stock Option Excluding Bonus Compensation [Member] An arrangement whereby an employee is entitled to receive in the future, subject to vesting and other restrictions, a number of shares in the entity at a specified price, as defined in the agreement, excluding options granted as bonus compensation. Minimum Minimum [Member] Cost of revenue Cost of Sales [Member] Research and development Research and Development Expense [Member] General and administrative General and Administrative Expense [Member] Stock-based compensation Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Share-based compensation expense (in dollars) Allocated Share-based Compensation Expense Unrecognized compensation expense (in dollars) Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options Period over which unrecognized compensation expense expected to be recognized Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Assumptions used to calculate estimated fair value of stock options using the Black-Scholes option-pricing valuation model Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] Weighted-average volatility, low end of range (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum Weighted-average volatility, high end of range (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum Weighted-average expected term Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Risk free interest rate, maximum Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum Risk free interest rate, minimum Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum Risk free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Expected dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Concentration Risk Concentration Risk Schedule of the Company's third-party payers as a percentage of total Schedules of Concentration of Risk, by Risk Factor [Table Text Block] Revenue Recognition Revenue Recognition [Abstract] Schedule of Revenue recognized when cash is received and on an accrual basis Schedule of Revenue Recognition, Cash and Accrual Basis [Table Text Block] Tabular disclosure of recognition of revenue when cash is received and on an accrual basis. Summary of activity under the Company's stock option plans Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Summary of stock-based compensation expense Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Schedule of assumptions used to calculate estimated grant date fair value of stock options using the Black-Scholes option-pricing valuation model Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Schedule of grant date fair value of the ESPP shares was calculated using Black Scholes option Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block] Schedule of Operating Leased Assets [Table] Schedule of Operating Leased Assets [Table] Lease Arrangement, Type [Axis] Lease Arrangement, Type [Axis] Lease Arrangement, Type [Domain] Lease Arrangement, Type [Domain] Headquarters and laboratory facilities, South San Francisco, Lease signed April 2015 Headquarters And Laboratory Facilities South San Francisco Lease Two [Member] Represents the lease for headquarters and laboratory space in South San Francisco, California that expires March 2026. Laboratory facilities, Austin, Texas Laboratory Facilities Austin Texas [Member] Represents the lease for laboratory facilities in Austin, Texas that expires July 2018. Other assets Other Noncurrent Assets [Member] Operating Leases Operating Leased Assets [Line Items] Amount of space leased Lessee Leasing Arrangements, Operating Leases, Space Leased Amount of space leased under the terms of the agreement. Security deposit Security Deposit Long term deposit consisting of letter of credit serving as security for lease Future minimum lease payments under non-cancelable operating leases Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2016 Operating Leases, Future Minimum Payments, Remainder of Fiscal Year 2017 Operating Leases, Future Minimum Payments, Due in Two Years 2018 Operating Leases, Future Minimum Payments, Due in Three Years 2019 Operating Leases, Future Minimum Payments, Due in Four Years 2020 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total minimum lease payments Operating Leases, Future Minimum Payments Due Facilities rent expense Operating Leases, Rent Expense, Net Supplies Purchase Commitments Purchase Obligation [Abstract] Number of suppliers Number of Suppliers With Purchase Obligations Number of suppliers with which the entity has non-cancelable purchase obligations. Non-cancelable purchase commitment Purchase Obligation Number of operating segments Number of Operating Segments Share Price Share Price Weighted average fair value of options to purchase common stock granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Intrinsic value of stock options exercised (in dollars) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Schedule of outstanding shares of common stock equivalents that have been excluded from diluted net loss per common share Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Receivable Type [Axis] Receivable Type [Axis] Receivable [Domain] Receivable [Domain] Accrued Income Receivable Accrued Income Receivable [Member] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Revenue recognized when cash is received Revenue Recognized Received In Cash Revenue recognized during the period based on cash receipts. Revenue recognized on accrual basis, percentage Revenue Recognized On Accrual Basis, Percentage Revenue Recognized On Accrual Basis, Percentage Revenue recognized on an accrual basis Revenue Recognized On Accrual Basis Revenue recognized during the period on an accrual basis. Revenue recognized received in cash, percentage Revenue Recognized Received In Cash, Percentage Revenue Recognized Received In Cash, Percentage Total Revenue, percent Revenue, Percent Revenue, Percent Accrued Liabilities Accounts Payable and Accrued Liabilities Disclosure [Text Block] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Thyroid Cytopathology Partners Variable Interest Entity, Not Primary Beneficiary [Member] Thyroid Cytopathology Partners Variable Interest Entity [Line Items] Notice of intent not to renew period Agreement Terms, Non-Renewal Notice Period Represents the minimum period required to provide notice of intent not to renew agreement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Expenses for cytopathology testing and evaluation services Testing and Evaluation Services Expense Testing and evaluation service costs directly related to generating revenues. Outstanding obligations Reduction to rent expense for TCP's portion of costs for subleased space Other Income Rent Reimbursement Amount of reimbursement from third party for rent and related operating expenses for shared space included in other income in the income statement. Schedule of Cash and Cash Equivalents [Table] Schedule of Cash and Cash Equivalents [Table] Headquarters and laboratory facility, South San Francisco, Lease expiring 2016 Headquarters And Laboratory Facility South San Francisco [Member] Represents the lease for headquarters and laboratory space in South San Francisco, California that expires March 2016. Cash and Cash Equivalents [Line Items] Cash and Cash Equivalents [Line Items] Restricted Cash Restricted Cash and Investments [Abstract] Cash reserved to cover liabilities associated with Merger Document and Entity Information Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Period End Date Document Period End Date Amendment Flag Amendment Flag Current Fiscal Year End Date Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus