Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Stock-Based Compensation - Plan Summary - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average derived service period		9 months 3 days
Stock-based compensation		$ 41,184	$ 32,938
Market Condition Awards Granted to Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 7,100	7,100
Stock-based compensation	$ 1,500	$ 4,600
2017 Inducement Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance	2,006,772	2,006,772
2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance	4,964,617	4,964,617
2015 Plan [Member] \| Market Condition Awards Granted to Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares Non-vested period	414,700	414,700		414,700