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Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Average remaining contractual life Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Aggregate intrinsic value, options vested and expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Shares issuable under options, options vested and expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Weighted-average exercise price, options vested and expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Average remaining contractual life, options vested and expected to vest Share Based Compensation Arrangement By Share Based Payment Award Options Weighted Average Remaining Contractual Term [Abstract] Share Based Compensation Arrangement By Share Based Payment Award Options Weighted Average Remaining Contractual Term [Abstract] Weighted-average remaining contractual life Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Outstanding Stock Maximum Percentage of outstanding shares of common stock Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent Options purchase price of common stock, percent of fair market value Equity Award [Domain] Equity Award [Domain] Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Weighted-average exercise price, exercised Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Weighted-average 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Stock Issued During Period Shares To Underwriters For Exercise Of Over Allotment Option Shares issued related to the exercise of over allotment option by underwriters Stock Issued During Period, Value, Conversion of Convertible Securities, Net of Adjustments Conversion of promissory notes and accrued interest to convertible preferred stock, value Stock Issued During Period, Value, New Issues Issuance of common stock Stock Issued During Period, Value, Stock Options Exercised Issuance of common stock upon exercise of stock options, value Equity Option [Member] Options to Purchase Common Stock [Member] Stock Repurchased and Retired During Period, Shares Reacquired and retired shares of restricted common stock Repurchase and retirement of common stock, at cost Subsequent Event [Line Items] Subsequent Event [Line Items] Subsequent Event [Member] Subsequent Event [Member] Subsequent Events [Abstract] Subsequent Events [Abstract] Subsequent Events [Text Block] Subsequent Events Subsequent Event [Table] Subsequent Event [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Licensed Product [Member] Subsequent Licensed Product [Member] Subsequent Licensed Product [Member] Sale of Stock [Axis] Sale of Stock [Axis] Summary of Valuation Allowance [Table Text Block] Summary of Changes in the Valuation Allowance for Deferred Tax Assets Supplemental Cash Flow Information [Abstract] Supplemental disclosure of cash flow information: Tax Credit Carryforward [Axis] Tax Credit Carryforward [Axis] Tax Credit Carry Forward Expiration Year Start Tax Credit Carry Forward Expiration Year Start Research and development tax credit carryforwards, beginning of expiration period Tax Credit Carryforward, Name [Domain] Tax Credit Carryforward, Name [Domain] Temporary Equity, Accretion to Redemption Value, Adjustment Accretion of redeemable convertible preferred stock to redemption values Accretion of redeemable convertible preferred stock to redemption value Temporary Equity, by Class of Stock [Table] Temporary Equity, by Class of Stock [Table] Temporary Equity [Line Items] Temporary Equity [Line Items] Temporary Equity, Liquidation Preference Liquidation Preference Redeemable convertible preferred stock (Series A, B, C, D and E), aggregate liquidation preference value Temporary Equity, Par or Stated Value Per Share Preferred stock, par value Redeemable convertible preferred stock (Series A, B, C, D and E), par value Temporary Equity, Shares Authorized Redeemable convertible preferred stock (Series A, B, C, D and E), shares authorized Preferred Shares Authorized Preferred stock, shares authorized Temporary Equity, Shares Issued Redeemable convertible preferred stock (Series A, B, C, D and E), shares issued Preferred Shares Issued Preferred stock, shares issued Temporary Equity, Shares Outstanding Temporary equity, ending balance, shares Temporary equity, beginning balance, shares Preferred Shares Outstanding Redeemable convertible preferred stock (Series A, B, C, D and E), shares outstanding Temporary Equity, Stock Issued During Period, Value, New Issues Issuance of redeemable convertible preferred stock, value Temporary Equity [Table Text Block] Schedule of Redeemable Preferred Stock Temporary Equity, Par Value Temporary equity, ending balance Temporary equity, beginning balance Redeemable convertible preferred stock (Series A, B, C, D and E), $0.001 par value; No shares and 99,292,610 shares authorized at December 31, 2014 and 2013, respectively; no shares and 94,483,404 shares issued and outstanding at December 31, 2014 and 2013, respectively; aggregate liquidation preference of $104,588 at December 31, 2013 Term Loan A [Member] Term Loan A [Member] Term Loan A [Member] Term Loan B And C [Member] Term Loan B And C [Member] Term Loan B and C [Member] Term Loan B [Member] Term Loan B [Member] Term Loan B [Member] Term Loan C [Member] Term Loan C [Member] Term Loan C [Member] Trading Symbol Trading Symbol Two Thousand And Fourteen Employee Stock Purchase Plan [Member] Two Thousand And Fourteen Employee Stock Purchase Plan [Member] 2014 Employee Stock Purchase Plan [Member] Two Thousand Fourteen Stock Option [Member] Two Thousand Fourteen Stock Option [Member] 2014 Stock Option and Incentive Plan [Member] Two Thousand Six Stock Option Plan [Member] Two Thousand Six Stock Option Plan [Member] 2006 Stock Option Plan [Member] Unrecognized Tax Benefits Unrecognized tax benefits Unvested restricted common stock. 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