Stockholders' Equity - Summary of Stock Option Activity and Weighted Average Exercise Prices (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Options
Options outstanding, beginning balance (in shares)	6,266	7,959	7,769
Granted (in shares)	1,425	2,033	2,042
Exercised (in shares)	(1,523)	(3,120)	(854)
Cancelled or expired (in shares)	(369)	(606)	(998)
Options outstanding, ending balance (in shares)	5,799	6,266	7,959
Options vested and expected to vest	5,096	5,550	7,163
Options exercisable	2,901	3,278	5,163
Weighted Average Exercise Price
Options outstanding, beginning balance (in dollars per share)	$ 12.13	$ 10.71	$ 10.88
Granted (in dollars per share)	29.76	15.00	9.87
Exercised (in dollars per share)	11.12	10.70	8.80
Cancelled (in dollars per share)	14.76	10.03	11.98
Options outstanding, ending balance (in dollars per share)	16.57	12.13	10.71
Options vested and expected to vest (in dollars per share)	15.29	11.89	10.75
Options exercisable (in dollars per share)	$ 12.03	$ 11.12	$ 11.17
Weighted Average Remaining Contractual Term (in years)
Options outstanding	6 years 9 months 14 days	6 years 6 months 18 days	5 years 10 months 6 days
Options vested and expected to vest	6 years 5 months 26 days	6 years 3 months 10 days	5 years 5 months 26 days
Options exercisable	4 years 11 months 12 days	4 years 7 months 20 days	4 years 6 months
Aggregate Intrinsic Value
Options outstanding	$ 119,064	$ 43,348	$ 14,881
Options vested and expected to vest	110,934	39,521	13,197
Options exercisable	$ 72,424	$ 25,367	$ 8,648