Stock-Based Compensation - Options Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Additional disclosures
Intrinsic value of options exercised (in dollars)	$ 2,785	$ 2,304	$ 65
Proceeds from stock options exercised (in dollars)	153	12	59
Tax benefit realized	$ 0	$ 0	$ 0
2016 Plan
Number of shares
Outstanding at beginning of period (in shares)	2,791,754	2,845,226	2,635,827
Granted (in shares)	479,010	365,098	259,928
Exercised (in shares)	(203,991)	(406,683)	(41,151)
Forfeited (in shares)	(7,083)	(11,887)	(9,378)
Outstanding at end of the period (in shares)	3,059,690	2,791,754	2,845,226
Options vested and expected to vest at end of the period (in shares)	3,059,690
Exercisable at end of period (in shares)	2,214,358
Weighted average exercise price
Outstanding at beginning of period (in dollars per share)	$ 3.27	$ 2.56	$ 2.20
Granted (in dollars per share)	14.56	6.42	6.01
Exercised (in dollars per share)	1.32	1.04	1.42
Forfeited (in dollars per share)	9.02	6.24	4.17
Outstanding at end of period (in dollars per share)	5.14	$ 3.27	$ 2.56
Options vested and expected to vest at end of period (in dollars per share)	5.14
Exercisable at end of period (in dollars per share)	$ 3.10
Weighted average remaining contractual term
Outstanding	6 years 2 months 12 days
Options vested and expected to vest at of the period	6 years 2 months 12 days
Exercisable	5 years 4 months 24 days
Aggregate intrinsic value
Outstanding (in dollars)	$ 30,178
Options vested and expected to vest at end of period (in dollars)	30,178
Exercisable (in dollars)	26,314
Stock options | 2016 Plan
Additional disclosures
Total unrecognized compensation cost (in dollars)	$ 4,221
Weighted average period expected to be recognized	2 years 2 months 12 days
Non-employee options | 2016 Plan
Number of shares
Outstanding at end of the period (in shares)	217,392
Additional disclosures
Unvested options (in shares)	1,777