Stock-Based Compensation - Aggregate Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Stock-based compensation
Total stock-based compensation expense	$ 3,678	$ 3,477	$ 7,060	$ 6,026
Stock Options
Stock-based compensation
Total stock-based compensation expense	2,041	1,820	4,715	3,279
Restricted stock units
Stock-based compensation
Total stock-based compensation expense	1,296	1,074	2,603	1,993
PSUs
Stock-based compensation
Total stock-based compensation expense	70	152	(761)	71
Employee stock purchase plan
Stock-based compensation
Total stock-based compensation expense	$ 271	$ 431	$ 503	$ 683