Statement of Financial Position [Abstract] Assets Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Accounts receivable Accounts Receivable, Net, Current Supplies Inventory, Net Prepaid expenses and other current assets Prepaid Expense and Other Assets, 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 Accrued Liabilities, Current Current portion of long-term debt Long-term Debt, Current Maturities Total current liabilities Liabilities, Current Long-term debt Long-term Debt, Excluding Current Maturities Capital lease liability, net of current portion Capital Lease Obligations 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 December 31, 2018 and 2017 Preferred Stock, Value, Issued Common stock, $0.001 par value; 125,000,000 shares authorized, 40,863,202 and 34,210,388 shares issued and outstanding as of December 31, 2018 and 2017, 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 Commitments and Contingencies Disclosure [Abstract] Schedule of Capital Leased Assets [Table] Schedule of Capital Leased Assets [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Equipment Equipment [Member] Capital Leased Assets [Line Items] Capital Leased Assets [Line Items] Capital leased assets Capital Leased Assets, Gross Capital lease, upfront payment Capital Lease, Upfront Payment Capital Lease, Upfront Payment Capital leases, future minimum payments, present value of net minimum payments Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments Annual future minimum lease payment Capital Leases, Future Minimum Payments Due, Next Twelve Months Quarterly Financial Information Disclosure [Abstract] Schedule of selected quarterly financial data (unaudited) Quarterly Financial Information [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Number of operating segments (in segments) Number of Operating Segments Income Tax Disclosure [Abstract] Income Tax Examination [Table] Income Tax Examination [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Federal Domestic Tax Authority [Member] State State and Local Jurisdiction [Member] Income tax examination Income Tax Examination [Line Items] Income tax examination period Income Tax Examination Period Period which will remain open for examination by tax authorities, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Organization and Description of Business Business Description and Basis of Presentation [Text Block] Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Additional Paid-in Capital Additional Paid-in Capital [Member] Accumulated Deficit Retained Earnings [Member] Statement Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Rollforward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance Balance (in shares) Shares, Outstanding Issuance of common stock on exercise of stock options Stock Issued During Period, Value, Stock Options Exercised Issuance of common stock on exercise of stock options (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Issuance of common stock on exercise of stock options and vesting of restricted stock units Share-based Compensation Arrangement by Share-based Payment Award, Value, Options and Non-Option Equity Instruments, Exercises in Period Share-based Compensation Arrangement by Share-based Payment Award, Value, Options and Non-Option Equity Instruments, Exercises in Period Issuance of common stock on exercise of stock options and vesting of restricted stock units (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options and Non-Option Equity Instruments, Exercises in Period Share-based Compensation Arrangement by Share-based Payment Award, Options and Non-Option Equity Instruments, Exercises in Period Issuance of common stock under employee stock purchase plan (ESPP) Stock Issued During Period, Value, Employee Stock Purchase Plan Issuance of common stock on employee stock purchase plan (ESPP) (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Sale of common stock in a private placement, net of issuance costs Stock Issued And Sold During Period Value In Private Placement Value of shares issued and sold during the period in a private placement. Sale of common stock in a private placement, net of issuance costs (in shares) Stock Issued And Sold During Period, Shares, In Private Placement Number of shares issued and sold during the period in a private placement. Stock-based compensation expense (employee) Adjustments to Additional Paid in Capital Share Based Compensation Employee Amount of increase in additional paid-in capital (APIC) resulting from employee stock-based compensation expense. Stock-based compensation expense (non-employee) Adjustments to Additional Paid in Capital Share Based Compensation Non Employee Amount of increase in additional paid-in capital (APIC) resulting from non-employee stock-based compensation expense. Stock-based compensation expense (ESPP) Adjustments To Additional Paid In Capital Share Based Compensation ESPP Amount of increase in additional paid-in capital (APIC) resulting from ESPP stock-based compensation expense. Legal settlement from short-swing profits, net of tax Legal Settlement Regarding Short-Swing Profits, Net Of Tax Legal Settlement Regarding Short-Swing Profits, Net Of Tax Net loss Net Income (Loss) Available to Common Stockholders, Basic Net loss and comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Balance Balance (in shares) Accounting Policies [Abstract] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Product Product [Member] Service Service [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] ASU 2014-09 Accounting Standards Update 2014-09 [Member] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Biopharmaceutical Company Biopharmaceutical Company [Member] Biopharmaceutical Company [Member] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Useful lives Property, Plant and Equipment, Useful Life Finite-lived Intangible Assets Finite-Lived Intangible Assets, Gross [Abstract] Useful life Finite-Lived Intangible Asset, Useful Life Finite-lived intangible assets, impairment Impairment of Intangible Assets, Finite-lived Goodwill Goodwill, Impaired [Abstract] Goodwill impairment Goodwill, Impairment Loss Revenue Recognition Revenue Recognition [Abstract] Revenue recognized on an accrual basis Revenue Recognized On Accrual Basis Revenue recognized during the period on an accrual basis. Revenue recognized on accrual basis, percentage Revenue Recognized On Accrual Basis, Percentage Revenue Recognized On Accrual Basis, Percentage Revenue recognized on a cash basis Revenue Recognized Received In Cash Revenue recognized during the period based on cash receipts. Revenue recognized on a cash basis, percentage Revenue Recognized Received In Cash, Percentage Revenue Recognized Received In Cash, Percentage Total Revenue from Contract with Customer, Excluding Assessed Tax Total, percentage Revenue, Percent Revenue, Percent Deferred revenue Contract with Customer, Liability Contract with customer, revenue recognized Contract with Customer, Liability, Revenue Recognized Income (loss) from operations Operating Income (Loss) Net income (loss) per common share, basic and diluted (in dollars per share) Earnings Per Share, Basic and Diluted Revenue, amount of remaining performance obligation Revenue, Remaining Performance Obligation, Amount Revenue, quarterly amount of remaining performance obligation Revenue, Remaining Performance Obligation, Amount, Per Quarter Revenue, Remaining Performance Obligation, Amount, Per Quarter Contract agreement term Term, Contract Agreement Term, Contract Agreement Automatic renewal period of contract agreement Automatic Renewal Period, Contract Agreement Automatic Renewal Period, Contract Agreement 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 Shell Company Entity Shell Company Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Public Float Entity Public Float 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 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 (in shares) Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Common stock, shares outstanding Common Stock, Shares, Outstanding Income Taxes Income Tax 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. Cash Equivalents Cash and Cash Equivalents, Unrestricted Cash and Cash Equivalents, Policy [Policy Text Block] Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Property and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Finite-lived Intangible Assets Intangible Assets, Finite-Lived, Policy [Policy Text Block] Goodwill Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block] Fair Value of Financial Instruments Fair Value of Financial Instruments, Policy [Policy Text Block] Revenue Recognition and Cost of Revenue Revenue from Contract with Customer [Policy Text Block] Research and Development Research and Development Expense, Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Stock-based Compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Net Loss per Common Share Earnings Per Share, Policy [Policy Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Thyroid Cytopathology Partners Thyroid Cytopathology Partners Long-term Contracts or Programs Disclosure [Text Block] Subsequent Events [Abstract] Subsequent Event [Table] Subsequent Event [Table] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving credit facility Revolving Credit Facility [Member] 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] Lender Name [Axis] Lender Name [Axis] Line of Credit Facility, Lender [Domain] Line of Credit Facility, Lender [Domain] Silicon Valley Bank Silicon Valley Bank [Member] Silicon Valley Bank [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Repayments of long-term debt Repayments of Long-term Debt Statement of Cash Flows [Abstract] Operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] 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 Other income Other Operating Activities, Cash Flow Statement Conversion of accrued interest to long-term debt Paid-in-Kind Interest Amortization and write-off of debt discount and issuance costs Amortization of Debt Issuance Costs and Discounts Interest on end-of-term debt obligation and prepayment penalty Debt instrument, End of Term Payment Interest Amount and Prepayment Penalty Debt instrument, End of Term Payment Interest Amount and Prepayment Penalty Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable Increase (Decrease) in Accounts Receivable Supplies Increase (Decrease) in Inventories Prepaid expenses and other current 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 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 Proceeds from the sale of property and equipment Proceeds from Sale of Property, Plant, and Equipment Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities 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 issuance of common stock in a public offering, net of issuance costs Proceeds from Issuance Initial Public Offering 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 legal settlement regarding short-swing profits Proceeds from Legal Settlements Payment of capital lease liability Repayments of Long-term Capital Lease Obligations Proceeds from the exercise of common stock options and employee stock purchases Proceeds from Stock Options Exercised Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Net increase (decrease) in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash, cash equivalents and restricted cash at beginning of year Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents and restricted cash at end of year Supplementary cash flow information of non-cash investing and financing activities: Noncash Investing and Financing Items [Abstract] Net receivable for reimbursement of public offering issuance costs Reimbursement of Offering Costs Reimbursement of Offering Costs Purchases of property and equipment included in accounts payable and accrued liabilities Capital Expenditures Incurred but Not yet Paid Supplementary cash flow information: Supplemental Cash Flow Information [Abstract] Cash paid for interest on debt Interest Paid, Excluding Capitalized Interest, Operating Activities Cash paid for tax Income Taxes Paid Restricted cash - current Restricted Cash and Cash Equivalents, Current Restricted cash - long-term Total cash, cash equivalents and restricted cash Debt Disclosure [Abstract] Schedule of net debt obligation Schedule of Debt [Table Text Block] Schedule of future principal payments under the Amended Loan Contractual Obligation, Fiscal Year Maturity Schedule [Table Text Block] Schedule of interest expense on debt Interest Income and Interest Expense Disclosure [Table Text Block] Selected Quarterly Financial Data (Unaudited) Selected Quarterly Financial Information [Abstract] Revenue Net loss per common share, basic and diluted (in dollars per share) Shares use to compute net loss per common share, basic and diluted (in shares) Weighted Average Number of Shares Outstanding, Basic and Diluted Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] 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. Stock-based Compensation, non-employees Non Employee Stock Option [Member] An arrangement whereby a 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. Employee stock purchase plan Employee Stock [Member] Stock incentive plans Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Summary of activity under the Company's stock option plans Share-based Compensation, Stock Options, Activity [Table Text Block] Summary of share-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] Fair Value Disclosures [Abstract] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Money Market Funds Money Market Funds [Member] 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 in 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. Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Security deposit Security Deposit 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, Net [Member] 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] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Medicare Medicare [Member] Represents information pertaining to Medicare, a significant third-party payer. United Healthcare United Healthcare [Member] Represents information pertaining to United Healthcare, a significant third-party payer. Headquarters and laboratory facilities, South San Francisco, Lease expiring 2016 Headquarters And Laboratory Facilities South San Francisco [Member] Represents the lease for headquarters and laboratory space in South San Francisco, California that expires March 2016. 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 (in financial institutions) 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 Restricted Cash Restricted Cash and Investments [Abstract] Long term deposit consisting of letter of credit serving as security for lease 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. 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] Revenues [Abstract] Revenues [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. Retirement Benefits [Abstract] 401(k) Plan Pension and Other Postretirement Benefits Disclosure [Text Block] Equity [Abstract] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Prepaid expenses and other current assets Prepaid Expenses and Other Current Assets [Member] 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. Sale of Stock [Axis] Sale of Stock [Axis] Sale of Stock [Domain] Sale of Stock [Domain] Over-Allotment Option Over-Allotment Option [Member] Class of Stock [Line Items] Class of Stock [Line Items] Common Stock Common Stock [Abstract] No definition available. Par value of shares of common stock (in dollars per share) Number of votes for each share of stock (in votes) Voting Rights for Each Share of Stock Represents the number of votes for each share of stock. Dividends declared Dividends Payable Options issued and outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Shares available for issuance (in shares) 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 Shares issued, price per share (in usd per share) Shares Issued, Price Per Share Proceeds from issuance of common stock Sale of Stock, Consideration Received on Transaction Payments of stock issuance costs Payments of Stock Issuance Costs Number of shares issued in transaction (in shares) Sale of Stock, Number of Shares Issued in Transaction Accounts receivable Accounts Receivable, Gross Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Debt Instrument [Line Items] Debt Instrument [Line Items] Debt principal Debt Instrument, Face Amount End-of-term debt obligation Debt instrument end of term payment interest amount Represents the amount of interest end of term payment of debt. Unamortized debt issuance costs Debt Instrument, Unamortized Discount Net debt obligation Long-term Debt 2019 Long-term Debt, Maturities, Repayments of Principal in Year Two 2020 Long-term Debt, Maturities, Repayments of Principal in Year Three 2021 Long-term Debt, Maturities, Repayments of Principal in Year Four 2022 Long-term Debt, Maturities, Repayments of Principal in Year Five Total Long-term Debt, Gross Stock Incentive Plans Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Deferred tax assets: Components of Deferred Tax Assets Non Current [Abstract] Net operating loss carryforwards Deferred Tax Assets, Operating Loss Carryforwards Research and development credits Deferred Tax Assets Tax Credit Carryforwards Research and Development Represents the amount before allocation of valuation allowances of deferred tax asset attributable to deductible research and development tax credit carryforwards. Stock-based compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Accruals, deferred rent and other Deferred Tax Assets Accruals, Deferred Rent and Other Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from non-current accruals, deferred rent and other reserves and accruals not separately disclosed. Gross deferred tax assets Deferred Tax Assets, Gross, Noncurrent Valuation allowance Tax Credit Carryforward, Valuation Allowance Net deferred tax assets Deferred Tax Assets, Net of Valuation Allowance Deferred tax liabilities: Components of Deferred Tax Liabilities Non Current [Abstract] Property and equipment Deferred Tax Liabilities, Property, Plant and Equipment In-process research and development Deferred Tax Liabilities, Deferred Expense, Capitalized Research and Development Costs Gross deferred tax liabilities Deferred Tax Liabilities, Gross Net deferred tax liabilities Deferred Tax Liabilities, Net Net deferred taxes Deferred Tax Assets, Net Schedule of Operating Leased Assets [Table] Schedule of Operating Leased Assets [Table] Laboratory facilities, Austin, Texas Laboratory Facilities Austin Texas [Member] Represents the lease for laboratory facilities in Austin, Texas that expires July 2018. Operating Leases Operating Leased Assets [Line Items] Amount of space leased (in square feet) Lessee Leasing Arrangements, Operating Leases, Space Leased Amount of space leased under the terms of the agreement. Future minimum lease payments under non-cancelable operating leases Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2019 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2020 Operating Leases, Future Minimum Payments, Due in Two Years 2021 Operating Leases, Future Minimum Payments, Due in Three Years 2022 Operating Leases, Future Minimum Payments, Due in Four Years 2023 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] Non-cancelable purchase commitment Purchase Obligation Genzyme Co-Promotion Agreement Genzyme Co-Promotion Agreement Collaborative Arrangement Disclosure [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] Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Share-based compensation award, tranche one Share-based Compensation Award, Tranche One [Member] Share-based compensation award, tranche two Share-based Compensation Award, Tranche Two [Member] Share-based compensation award, tranche three Share-based Compensation Award, Tranche Three [Member] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 2008 Plan Stock Plan2008 [Member] Represents information pertaining to the 2008 Stock Plan (the 2008 Plan). Stock Incentive Plan 2013 Stock Incentive Plan2013 [Member] Represents information pertaining to the 2013 Stock Incentive Plan (the 2013 Plan). ISO Incentive Stock Options [Member] Represents information pertaining to incentive stock options (ISOs). NSO Non Statutory Stock Options [Member] Represents information pertaining to non statutory stock options (NSOs). Employee stock options Employee Stock Option [Member] Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Outside director who was not previously an employee Outside Director Who Was Not Previously Employee [Member] Represents information pertaining to outside director, who was not previously an employee. Outside director serving as a member of Board of Directors for at least six months Outside Director Serving As Member Of Board Of Directors For At Least Six Months [Member] Represents information pertaining to outside director serving as a member of Board of Directors for at least six months. Outside director Outside Director [Member] Nonemployee serving on the board of directors (who collectively have responsibility for governing the entity). Term of options granted Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Voting power of person owning stock Share Based Compensation Arrangement by Share Based Payment Award Percentage of Voting Power of All Classes of Stock Voting power of all classes of stock, as a percent, of person owning stock as threshold for option terms under the entity's stock option plan. Term of options granted to a person owning stock representing more than 10% of voting power of all classes of stock Share Based Compensation Arrangement by Share Based Payment Award Term of Options Granted to Employees Who Owned Specified Percentage of Class of Stock Represents the term of options granted to persons owning stock representing specified percentage of voting power of all classes of stock, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Minimum purchase price as a percentage of fair market value Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent Option price as a percentage of estimated fair value of shares on date of grant to a person owning stock representing more than 10% of voting power of all classes of stock Share based Compensation Arrangement by Share based Payment Award Purchase Price of Stock Percentage for Grants to Persons Who Owned Specified Percentage of Class of Stock Option price as a percentage of estimated fair value of shares on date of grant to a person owning stock representing specified percentage of voting power of all classes of stock. Percentage of award vesting after one year Share based Compensation Arrangement by Share based Payment Award Award Vesting Rights Percentage Year One Percentage of vesting of share-based compensation awards after one year from date of grant. Vesting rights, percentage Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Number of additional shares reserved for issuance (in shares) Common Stock Capital Additional Shares Reserved for Future Issuance Aggregate number of additional common shares reserved for future issuance under the plan. Maximum annual increase in outstanding shares on the last day of the immediately preceding fiscal year (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Outstanding Stock Maximum Number of shares available for issuance (in shares) Shares granted as initial grant (in shares) Share Based Compensation Arrangement by Share Based Payment Award Options Initial Grants Gross number of share options (or share units) granted to each individual as an initial grant. Shares granted as annual grant (in shares) Share Based Compensation Arrangement by Share Based Payment Award Options Annual Grants Gross number of share options (or share units) granted to each individual as an annual grant. Period for which director has to serve as board of director to receive grant to purchase shares Share Based Compensation Arrangement by Share based Payment Award Period for Which Director Has to Serve as Board of Director to Receive Grant to Purchase Shares Represents the period for which director has to serve as board of director to receive grant to purchase shares. Expiration period after termination of service Share Based Compensation Arrangement by Share Based Payment Award Award Expiration Period After Termination Expiration period of award after termination of service, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Line of Credit Facility [Table] Line of Credit Facility [Table] Debt Prepayment Tranche [Axis] Debt Prepayment Tranche [Axis] Debt Prepayment Tranche [Axis] Debt Payment Tranche [Domain] Debt Payment Tranche [Domain] [Domain] for Debt Payment Tranche [Axis] Debt prepayment tranche one Debt Prepayment Tranche One [Member] Debt Prepayment Tranche One [Member] Debt prepayment tranche two Debt Prepayment Tranche Two [Member] Debt Prepayment Tranche Two [Member] Debt prepayment tranche three Debt Prepayment Tranche Three [Member] Debt Prepayment Tranche Three [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR London Interbank Offered Rate (LIBOR) [Member] Secured Debt Secured Debt [Member] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Line of credit facility, maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Interest rate, stated percentage Debt Instrument, Interest Rate, Stated Percentage Effective interest rate Debt Instrument, Interest Rate, Effective Percentage Prepayment premium Debt Instrument, Prepayment Premium Amount of prepayment premium waived. Periodic payment terms, balloon payment to be paid Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid Minimum requirement liability Liquidity Requirement, Minimum Liquidity Requirement, Minimum Unamortized debt issuance costs Debt Issuance Costs, Current, Net Selected Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Employer contributions to the plan Defined Contribution Plan, Cost Reconciliation of the beginning and ending amount of unrecognized tax benefits Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Unrecognized tax benefits, beginning of period Unrecognized Tax Benefits Gross increases—tax position in prior period Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Gross decreases—tax position in prior period Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Gross increases—current period tax position Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Lapse of statute of limitations Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Unrecognized tax benefits, end of period Interest expense or penalties related to unrecognized tax benefits Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense Fair Value Measurements Fair Value Disclosures [Text Block] Nominal debt interest Interest Expense, Debt, Excluding Amortization Amortization and write-off of debt discount and issuance costs Amortization of Debt Discount (Premium) End-of-term debt obligation interest Debt prepayment penalty Prepayment Penalty Prepayment penalty. Interest on capital lease Interest Expense, Lessee, Assets under Capital Lease Total Interest Expense, Debt Balance Sheet Related Disclosures [Abstract] Balance Sheet Components Supplemental Balance Sheet Disclosures [Text Block] Maximum offering period Share-based Compensation Arrangement by Share-based Payment Award, Offering Period, Maximum The maximum offering period under the plan, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Purchase period Share-based Compensation Arrangement by Share-based Payment Award, Purchase Period The purchase period under the plan, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Maximum fair market value of shares an employee can purchase per calendar year Share-based Compensation Arrangement by Share-based Payment Award, Maximum Value of Shares Per Employee The maximum fair market value of shares an employee can purchase under the plan per calendar year. Earnings Per Share [Abstract] Net Loss Per Share Earnings Per Share [Text Block] Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] 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. Liquidity Liquidity [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Accumulated deficit Proceeds from long-term lines of credit Proceeds from Long-term Lines of Credit Calculation of basic and diluted net loss per common share Earnings Per Share, Basic and Diluted [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] Restricted stock units Restricted Stock Units (RSUs) [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] Shares of common stock subject to outstanding options (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Debt Debt Disclosure [Text Block] Schedule of reconciliation of tax expense computed at the statutory federal rate and the Company's tax expense Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of significant components of the Company's deferred tax assets and liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Schedule of reconciliation of the beginning and ending amount of unrecognized tax benefits Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Accrued Liabilities Accrued Liabilities, Current [Abstract] Accrued compensation expense Employee-related Liabilities, Current Accrued other Other Accrued Liabilities, Current Total accrued liabilities 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. Number of term loans (in term loans) Number Of Term Loans Represents the number of term loans available to the Company. Proceeds from lines of credit Proceeds from Lines of Credit Number of installments (in 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. Prepayment premium Debt Instrument Penalty Percentage On Prepayment Period One Represents the percentage of prepayment premium for prepayment made on or prior to March 31, 2018. Fixed rate percentage paid in cash Debt Instrument Fixed Rate Percentage Paid In Cash Rate for which Company may elect to pay interest in cash. Interest paid-in-kind percentage 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. Prepayment premium Income Statement [Abstract] 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 Total operating expenses Operating Expenses Loss from operations Interest expense Interest Expense Other income, net Other Nonoperating Income (Expense) Net loss Comprehensive loss 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 Tax portion of restricted stock units vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares, Tax Portion Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares, Tax Portion 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) Exercised (in shares) Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares 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 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 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 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 (in dollars) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value 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 Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Cost of revenue Cost of Sales [Member] Research and development Research and Development Expense [Member] Selling and marketing Selling and Marketing 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, low end of range (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum Risk-free interest rate, high end of range (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum Subsequent Event (Unaudited) Subsequent Events [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] Direct monetary compensation Increase (Decrease) in Contract with Customer, Liability 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. Contract termination fee Contract Termination Fee Contract Termination Fee Quarterly installments (in installments) Payment Installments for Contract Termination Fee Payment Installments for Contract Termination Fee 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 shared 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. Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Leasehold improvements Leasehold Improvements [Member] Laboratory equipment Computer equipment Computer Equipment [Member] Software, including software developed for internal use Software and Software Development Costs [Member] Furniture and fixtures Furniture and Fixtures [Member] Construction-in-process Construction in Progress [Member] Property and Equipment, Net Property, Plant and Equipment [Line Items] Total property and equipment, at cost Property, Plant and Equipment, Gross Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Total property and equipment, net Depreciation and amortization expense Depreciation and Amortization of Tangible Assets Depreciation and Amortization of Tangible Assets Capital leases, accumulated depreciation Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation Capital leases, depreciation expense Capital Leases, Lessee Balance Sheet, Assets by Major Class, Depreciation Expense Capital Leases, Lessee Balance Sheet, Assets by Major Class, Depreciation Expense Reconciliation of tax expense computed at the statutory federal rate and the Company's tax expense Effective Income Tax Rate Reconciliation, Amount [Abstract] U.S. federal taxes at statutory rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount State tax (net of federal benefit) Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Non deductible officers's compensation Effective Income Tax Rate Reconciliation, Nondeductible Expense, Officer Compensation, Amount Effective Income Tax Rate Reconciliation, Nondeductible Expense, Officer Compensation, Amount Permanent differences Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount Incentive stock options Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount Tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Amount Change in valuation allowance Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount Rate differential impact - Tax Cuts and Jobs Act Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Total Income Tax Expense (Benefit) Intangible asset amortization Amortization of Intangible Assets Accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Annual amortization expense expected to be recognized annually Finite-Lived Intangible Assets, Annual Amortization Expense Amount of annual amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized over the useful life of the assets. Schedule of property and equipment Property, Plant and Equipment [Table Text Block] Schedule of accrued liabilities Schedule of Accrued Liabilities [Table Text Block] Pretax loss Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax expense (benefit) Tax Cuts and Jobs Act of 2017, deferred tax asset decrease Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense Increase (decrease) in valuation allowance against deferred tax assets Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Share-based compensation excess tax benefit amount Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Amount Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] California CALIFORNIA Other state income tax purposes Other States, Not Separately Disclosed [Member] Other States, Not Separately Disclosed [Member] Operating loss carryforwards Operating Loss Carryforwards [Line Items] Net operating loss carryforwards Operating Loss Carryforwards Tax credit carryforward Tax Credit Carryforward, Amount Share price (in dollars per share) 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 Total estimated grant date fair value of options to purchase common stock vested (in dollars) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, 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 Weighted average grant date fair value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Intrinsic value of stock options outstanding 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 Collaborative Arrangements and Non-collaborative Arrangement Transactions [Table] Schedule of Collaborative Arrangements and Non-collaborative Arrangement Transactions [Table] 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. Genzyme Genzyme Corporation [Member] Represents information pertaining to Genzyme Corporation, a co-promoter. 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 expenses Collaborative Arrangement Co Promotion Expenses Represents the amount of co-promotion expenses incurred under the agreement. Outstanding obligation to Genzyme Collaborative Arrangement Outstanding Obligation Represents the amount of outstanding obligation under the agreement. Amortization of up-front co-promotion fee Common stock private placement costs Common Stock Issued Issuance Costs Private Placement Represents issuance costs pertaining to the sale of common stock in a private placement.