Common Stock and Stockholders' Equity (Deficit) - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Outstanding at the beginning of period	4,311,463
Number of Shares, Granted	513,569
Number of Shares, Exercised	(102,050)
Number of Shares, Forfeited or cancelled	(75,036)
Number of Shares, Outstanding at the end of period	4,647,946	4,311,463
Number of Shares, Exercisable	2,176,598
Number of Shares, Vested and expected to vest	4,553,559
Weighted Average Exercise Price, Outstanding at the beginning of period	$ 9.87
Weighted Average Exercise Price, Granted	13.77
Weighted Average Exercise Price, Exercised	2.96
Weighted Average Exercise Price, Forfeited or cancelled	11.99
Weighted Average Exercise Price, Outstanding at the end of period	10.41	$ 9.87
Weighted Average Exercise Price, Exercisable	7.10
Weighted Average Grant Date Fair Value, Vested and expected to vest	$ 10.35
Weighted Average Remaining Contractual Life (years), Outstanding	8 years	7 years 10 months 24 days
Weighted Average Remaining Contractual Life (years), Granted	10 years
Weighted Average Remaining Contractual Life (years), Options exercisable	6 years 8 months 12 days
Weighted Average Remaining Contractual Life (years), Options vested and expected to vest	7 years 10 months 24 days
Aggregate Intrinsic Value, Unvested balance at the beginning of period	$ 22,709
Aggregate Intrinsic Value, Unvested balance at the end of period	15,959	$ 22,709
Aggregate Intrinsic Value, Options Exercisable	14,001
Aggregate Intrinsic Value, Options vested and expected to vest	$ 15,909