Equity Compensation Plans - Summary of Stock Option Activity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares Underlying Options, Outstanding, Balance | shares	9,277,000
Shares Underlying Options, Granted | shares	1,640,000
Shares Underlying Options, Exercised | shares	(2,679,000)
Shares Underlying Options, Cancelled | shares	(4,054,000)
Shares Underlying Options, Outstanding, Balance | shares	4,184,000	9,277,000
Shares Underlying Options, Options vested and exercisable | shares	1,846,000
Shares Underlying Options, Options vested and expected to vest | shares	3,868,000
Weighted-Average Exercise Price, Outstanding, Balance | $ / shares	$ 1.36
Weighted-Average Exercise Price, Granted | $ / shares	3.09
Weighted-Average Exercise Price, Exercised | $ / shares	1.08
Weighted-Average Exercise Price, Cancelled | $ / shares	1.95
Weighted-Average Exercise Price, Outstanding, Balance | $ / shares	1.64	$ 1.36
Weighted-Average Exercise Price, Options vested and exercisable | $ / shares	1.37
Weighted-Average Exercise Price, Options vested and expected to vest | $ / shares	$ 1.62
Weighted-Average Remaining Contractual Term, Outstanding, Balance	7 years 3 months 18 days
Weighted-Average Remaining Contractual Term, Options vested and exercisable	6 years 9 months 18 days
Weighted-Average Remaining Contractual Term, Options vested and expected to vest	7 years 2 months 12 days
Aggregate Intrinsic Value | $	$ 4,876	$ 76,488
Aggregate Intrinsic Value, Options vested and exercisable | $	2,562
Aggregate Intrinsic Value, Options vested and expected to vest | $	$ 4,616