Stock-Based Compensation - Stock Options (Details) - Employee and non-employee stock options $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($) $ / shares shares
Stock Based Compensation
Shares available for grant, beginning balance	3,743
Additional shares authorized	2,014
Options granted (in shares)	(2,199)
Options forfeited (in shares)	751
Shares available for grant, end balance	4,309
Number of shares
Outstanding, beginning balance (in shares)	9,316
Options granted (in shares)	2,199
Options exercised (in shares)	(1,618)
Options forfeited (in shares)	(751)
Outstanding, end balance (in shares)	9,146
Exercisable (in shares)	4,819
Vested and expected to vest (in shares)	8,761
Weighted-Average Exercise Price
Outstanding, beginning balance (in dollars per share) | $ / shares	$ 3.96
Granted (in dollars per share) | $ / shares	10.06
Exercised (in dollars per share) | $ / shares	1.68
Forfeited (in dollars per share) | $ / shares	8.15
Outstanding, end balance (in dollars per share) | $ / shares	5.47
Exercisable (in dollars per share) | $ / shares	2.75
Vested and expected to vest (in dollars per share) | $ / shares	$ 5.33
Additional disclosures
Weighted average contractual term, options outstanding	7 years 8 months 12 days
Exercisable (in years)	6 years 7 months 2 days
Vested and expected to vest (in years)	7 years 7 months 13 days
Aggregate intrinsic value, options outstanding | $	$ 53,338
Aggregate intrinsic value, options exercisable | $	40,763
Aggregate intrinsic value, vested and expected to vest | $	$ 52,219