Stock-Based Compensation Expense - Stock Based Compensation Expense Recognized in Condensed Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock compensation expense	$ 3,179	$ 1,294	$ 9,040	$ 4,607
RSUs and Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock compensation expense	2,983	1,225	8,628	4,413
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock compensation expense	$ 196	$ 69	$ 412	$ 194