Stockholders' Equity - Summary of Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares Available for Grant, Beginning Balance	751,661	977,297
Shares Available for Grant, Shares reserved for issuance		1,345,430
Shares Available for Grant, Increase to Authorized Shares	1,500,000
Shares Available for Grant, Options granted	(620,702)	(1,687,484)
Shares Available for Grant, Options forfeited	259,599	104,787
Shares Available for Grant, Options cancelled	534	11,631
Shares Available for Grant, Ending Balance	1,891,092	751,661	977,297
Number of Options Outstanding, Beginning Balance	2,303,862	784,790
Number of Options Outstanding, Options granted	620,702	1,687,484
Number of Options Outstanding, Options exercised	(129,809)	(51,994)
Number of Options Outstanding, Options forfeited	(259,599)	(104,787)
Number of Options Outstanding, Options cancelled	(534)	(11,631)
Number of Options Outstanding, Ending Balance	2,534,622	2,303,862	784,790
Number of Options Outstanding, Exercisable	905,669
Number of Options Outstanding, Vested and expected to vest	2,386,820
Weighted-Average Exercise Price Per Option, Beginning Balance	$ 3.60	$ 0.83
Weighted Average Exercise Price Per Option, Options granted	11.78	4.64
Weighted-Average Exercise Price Per Option, Options exercised	1.21	1.34
Weighted-Average Exercise Price Per Option, Options forfeited	4.83	1.01
Weighted-Average Exercise Price Per Option, Options cancelled	5.44	1.59
Weighted-Average Exercise Price Per Option Ending Balance	5.60	$ 3.60	$ 0.83
Weighted-Average Exercise Price Per Option, Exercisable	2.79
Weighted-Average Exercise Price Per Options, Vested and expected to vest	$ 5.42
Weighted-Average Remaining Contact Term (Years)	8 years 6 months	9 years 2 months 5 days	9 years 4 days
Weighted-Average Remaining Contact Term (Years), Exercisable	7 years 7 months 28 days
Weighted-Average Remaining Contact Term (Years), Vested and expected to vest	8 years 4 months 21 days
Aggregate Intrinsic Value, Balance	$ 32,126	$ 13,593	$ 1,074
Aggregate Intrinsic Value, Exercisable	14,021
Aggregate Intrinsic Value, Vested and expected to vest	$ 30,685