Stock-Based Compensation (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Stock-Based Compensation
Stock-based compensation expense	$ 3,200			$ 2,900			$ 9,000	$ 7,700
Exercise of stock options (in shares)				458
Proceeds from exercise of stock options							$ 3,419	$ 7,740
Common Stock
Stock-Based Compensation
Exercise of stock options (in shares)	34	72	268	53	343	540
Common Stock | 2020 Employee stock purchase plan
Stock-Based Compensation
Exercise of stock options (in shares)	40			100			700	1,300
Proceeds from exercise of stock options	$ 300			$ 500			$ 3,900	$ 8,200