Net Income (Loss) Per Share Attributable to Common Stockholders - Computation of Diluted Net Income (Loss) Per Share Attributable to Common Stockholders Effect in Antidilutive (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Redeemable Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share		7,885		7,885
Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share		25		25
Redeemable Convertible Preferred Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share		264		264
Unvested Shares of Common Stock Subject to Repurchase
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share		154	141	154
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	35	2,158	2,272	2,158