Document And Entity Information [Abstract] Document And Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Current Reporting Status Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Statement of Financial Position [Abstract] Statement [Line Items] Assets [Abstract] Assets Assets, Current [Abstract] Current assets: Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of period Cash and cash equivalents at beginning of period Cash and cash equivalents Cash and cash equivalents, Amortized Cost Available-for-sale Securities, Debt Securities, Current Short-term investments Accounts Receivable, Net Accounts receivable Contract with Customer, Asset, Net, Current Unbilled license revenue Prepaid Expense and Other Assets, Current Prepaid expenses and other current assets Assets, Current Current assets Total current assets Property, Plant and Equipment, Net Property and equipment, net Other Assets, Noncurrent Other assets Assets Total assets Liabilities and Equity [Abstract] Liabilities and stockholders' equity Liabilities, Current [Abstract] Current liabilities: Accounts Payable, Current Accounts payable Employee-related Liabilities, Current Accrued compensation and benefits Contract with Customer, Liability, Current Uncharged license fees Accrued Liabilities and Other Liabilities Accrued and other liabilities Accrued liabilities and other liabilities Liabilities, Current Current liabilities Total current liabilities Other Liabilities, Noncurrent Other long-term liabilities Liabilities Total liabilities Commitments and Contingencies Commitments and contingencies Stockholders' Equity Attributable to Parent [Abstract] Stockholders' equity: Preferred Stock, Value, Issued Preferred stock, $0.0001 par value; 5,000,000 shares authorized; no shares issued and outstanding as of March 31, 2018 and December 31, 2017, respectively. Common Stock, Value, Issued Common stock, $0.0001 par value; 300,000,000 shares authorized; 47,603,568 and 47,534,979 shares issued and outstanding as of March 31, 2018 and December 31, 2017, respectively. Additional Paid in Capital, Common Stock Additional paid-in capital Retained Earnings (Accumulated Deficit) Accumulated deficit Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive loss Stockholders' Equity Attributable to Parent Total stockholders' equity Liabilities and Equity Total liabilities and stockholders' equity Preferred Stock, Par or Stated Value Per Share Preferred stock, par value 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 or Stated Value Per Share Common stock, par value Common Stock, Shares Authorized Common stock, shares authorized Common Stock, Shares, Issued Common stock, shares issued Common Stock, Shares, Outstanding Common stock, shares outstanding Income Statement [Abstract] Statement [Table] Revenues [Abstract] Revenue: Revenues Licensing revenue Revenue Cost of Revenue Cost of revenue Gross Profit Gross profit Operating Expenses [Abstract] Operating expenses: Research and Development Expense Research and development General and Administrative Expense General and administrative Operating Expenses Total operating expenses Operating Income (Loss) Loss from operations Nonoperating Income (Expense) Other income, net Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Loss before provision for income taxes Income Tax Expense (Benefit) Provision for income taxes Net Income (Loss) Attributable to Parent Net loss Net loss Earnings Per Share, Basic and Diluted Net loss per common share, basic and diluted Net loss per share - basic and diluted Weighted Average Number of Shares Outstanding, Basic and Diluted Shares used in computing net loss per share - basic and diluted Weighted average common shares outstanding - basic and diluted Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Comprehensive loss: Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Unrealized (loss) gain on available-for-sale securities, net of tax Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive loss Statement of Cash Flows [Abstract] Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Operating activities Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net loss to net cash used in operating activities: Depreciation Depreciation expense Amortization of Debt Issuance Costs Amortization of deferred financing costs Cost of Services, Amortization Amortization of deferred compensation for services Accretion (Amortization) of Discounts and Premiums, Investments Amortization of premium on investment securities Share-based Compensation Stock-based compensation Increase (Decrease) in Operating Capital [Abstract] Changes in operating assets and liabilities: Increase (Decrease) in Accounts Receivable Accounts receivable Increase (Decrease) in Prepaid Expense and Other Assets Prepaid expenses and other assets Increase (Decrease) in Accounts Payable Accounts payable Increase (Decrease) in Employee Related Liabilities Accrued compensation and benefits Increase (Decrease) in Other Accrued Liabilities Accrued and other liabilities Net Cash Provided by (Used in) Operating Activities, Continuing Operations Net cash used in operating activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Investing activities Proceeds from Maturities, Prepayments and Calls of Short-term Investments Proceeds from maturities of investments Proceeds from Sale of Other Investments Sales and redemptions of investments Payments to Acquire Short-term Investments Purchases of investments Payments to Acquire Property, Plant, and Equipment Purchases of property and equipment Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net cash (used in) provided by investing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Financing activities Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options Proceeds from issuance of common stock under stock plans Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net cash provided by financing activities Cash and Cash Equivalents, Period Increase (Decrease) Net decrease in cash and cash equivalents Accounting Policies [Abstract] Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Organization and Basis of Presentation Significant Accounting Policies [Text Block] Summary of Significant Accounting Policies Cash and Cash Equivalents [Abstract] Cash, Cash Equivalents, and Short-term Investments [Text Block] Cash, Cash Equivalents and Investments Fair Value Disclosures [Abstract] Fair Value Disclosures [Text Block] Fair Value Measurements Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Stock-Based Compensation Earnings Per Share [Abstract] Earnings Per Share [Text Block] Net Loss Per Share Payables and Accruals [Abstract] Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block] Accrued and Other Liabilities NA. Collaboration and Licensing Agreements [Abstract] Collaborative Arrangement Disclosure [Text Block] Collaboration and Licensing Agreements Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Text Block] Contingencies Use of Estimates, Policy [Policy Text Block] Use of Estimates Accrued research and development expenses policy. Accrued Research and Development Expenses Policy [Policy Text Block] Accrued Research and Development Expenses Disclosure of accounting policy for revenue from contract with customer. Revenue from Contract with Customer [Policy Text Block] Revenue Recognition New Accounting Pronouncements, Policy [Policy Text Block] Recent Accounting Pronouncements Fair Value Measurement, Policy [Policy Text Block] Fair Value Measurements New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block] Schedule of adjustments of topic 606 Cash, Cash Equivalents and Investments [Table Text Block] Schedule of Securities Classified as Cash, Cash Equivalents and Short-term Investments Fair Value, Assets Measured on Recurring Basis [Table Text Block] Summary of Fair Value Measurements of Company's Financial Assets Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Summary of Stock-Based Compensation Recognized Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Computation of Basic and Diluted Loss Per Share Attributable to Common Stockholders Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Schedule of Accrued Liabilities and Other Liabilities Organization, Consolidation and Presentation of Financial Statements [Abstract] Number of Operating Segments Number of operating segments Cash and cash equivalents and short term investments. Cash Cash Equivalents And Short Term Investments [Table] Major Types of Debt and Equity Securities [Axis] Major Types Of Debt And Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] U S Treasury Securities [Member] U.S. Treasury Securities [Member] Corporate Debt Securities [Member] Corporate Bonds [Member] Commercial Paper Not Included With Cash And Cash Equivalents [Member] Commercial Paper (Investments) [Member] Asset Backed Securities [Member] Asset-Backed Securities [Member] Cash and Cash Equivalents [Axis] Restricted Cash And Cash Equivalents Cash And Cash Equivalents [Member] Cash and Cash Equivalents [Domain] Cash [Member] Cash [Member] Money Market Funds [Member] Money Market Funds [Member] Commercial Paper [Member] Commercial Paper (Cash Equivalents) [Member] Cash and cash equivalents and short term investments. Cash Cash Equivalents And Short Term Investments [Line Items] Cash Equivalents, at Carrying Value Cash and cash equivalents, at Carrying Value Cash and cash equivalents gross unrealized losses. Cash And Cash Equivalents Gross Unrealized Losses Cash and cash equivalents, Gross Unrealized Losses Cash and Cash Equivalents, Fair Value Disclosure Cash and cash equivalents, Fair Value Available-for-sale Securities, Amortized Cost Basis Short-term investments, Amortized Cost Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Short-term investments, Gross Unrealized Losses Available-for-sale Securities Short-term investments, Fair Value Cash, Cash Equivalents, and Short-term Investments Cash equivalents and short-term investments, Amortized Cost Cash, cash equivalents and short term investments gross unrealized losses. Cash Cash Equivalents And Short Term Investments Gross Unrealized Losses Cash equivalents and short-term investments, Gross Unrealized Losses Cash, cash equivalents and short term investments fair value disclosure. Cash Cash Equivalents And Short Term Investments Fair Value Disclosure Cash equivalents and short-term investments, Fair Value Range [Axis] Range [Member] Range [Domain] Maximum [Member] Maximum [Member] Available for sale securities contractual maturity period. Available For Sale Securities Contractual Maturity Period Available for sale securities contractual maturity period Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Investment in continuous unrealized loss position for more than one year Fair Value Measurements, Recurring and Nonrecurring [Table] Asset Class [Axis] Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation By Asset Class [Domain] Asset Class [Domain] Domestic Corporate Debt Securities Including Cash Equivalents [Member] Domestic Corporate Debt Securities Including Cash Equivalents [Member] Corporate Bonds [Member] Commercial Paper Cash Equivalents Including Securities [Member] Commercial Paper Cash Equivalents Including Securities [Member] Commercial Paper [Member] Measurement Frequency [Axis] Fair Value Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value Measurements Recurring [Member] Fair Value, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value Measurements Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value Inputs Level1 [Member] Level 1 [Member] Fair Value Inputs Level2 [Member] Level 2 [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Assets, Fair Value Disclosure [Abstract] Assets: Assets, Fair Value Disclosure Assets at fair value Fair Value, Assets, Level 1 to Level 2 Transfers, Amount Transfer of assets from Level 1 to Level 2 Fair Value, Assets, Level 2 to Level 1 Transfers, Amount Transfer of assets from Level 2 to Level 1 Share-based Compensation Arrangement by Share-based Payment Award, Options Outstanding, Weighted Average Exercise Price, and Additional Disclosures [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Options Outstanding, Weighted Average Exercise Price, and Additional Disclosures [Abstract] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Research And Development Expense [Member] Research and Development [Member] General And Administrative Expense [Member] General and Administrative [Member] Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Allocated Share-based Compensation Expense Stock-based compensation Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Employee Stock Purchase Plan [Member] Employee Stock Purchase Plan [Member] Employee Stock Purchase Plan [Member] Award Type [Axis] Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Equity Award [Domain] Employee Stock Option [Member] Options to Purchase Common Stock [Member] Restricted Stock Units R S U [Member] Restricted Stock Units (RSUs) [Member] Performance based restricted stock units. Performance Based Restricted Stock Units [Member] Performance-Based Restricted Stock Units (PSRUs) [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Number of vested shares Share-based Compensation Arrangement by Share-based Payment Award Accelerated Compensation Cost Recognized stock-based compensation related expense in connection with vesting of award granted Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Unrecognized stock based compensation expense Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Unrecognized stock based compensation expense, weighted-average remaining recognition period Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Number of options exercised Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Number of shares issued upon vesting of restricted stock units Stock Issued During Period, Shares, Employee Stock Purchase Plans Number of shares issued under ESPP