Stock-Based Compensation - Options Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Number of shares
Outstanding at beginning of period (in shares)	2,755,343
Granted (in shares)	5,000
Exercised (in shares)	(117,755)
Forfeited (in shares)	(15,095)
Outstanding at end of the period (in shares)	2,627,493
Options vested and expected to vest at end of the period (in shares)	2,627,493
Exercisable at end of period (in shares)	1,703,465
Weighted average exercise price
Outstanding at beginning of period (in dollars per share)	$ 25.10
Granted (in dollars per share)	68.10
Exercised (in dollars per share)	11.09
Forfeited (in dollars per share)	49.88
Outstanding at end of period (in dollars per share)	25.66
Options vested and expected to vest at end of period (in dollars per share)	25.66
Exercisable at end of period (in dollars per share)	$ 17.11
Weighted average remaining contractual term
Outstanding	6 years 8 months 12 days
Options vested and expected to vest at of the period	6 years 8 months 12 days
Exercisable	5 years 10 months 24 days
Aggregate intrinsic value
Outstanding (in dollars)	$ 73,345
Options vested and expected to vest at end of period (in dollars)	73,345
Exercisable (in dollars)	60,994
Additional disclosures
Intrinsic value of options exercised (in dollars)	4,581	$ 3,971
Proceeds from stock options exercised (in dollars)	1,153	$ 1,037
Stock options
Additional disclosures
Total unrecognized compensation cost (in dollars)	$ 22,007
Weighted average period expected to be recognized	2 years 6 months