Convertible Senior Notes - Schedule of Interest Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
0.375% Convertible Senior Notes Due 2025 [Member]
Debt Instrument [Line Items]
Contractual interest expense	$ 430	$ 431	$ 861	$ 862
Amortization of debt discount		4,510		8,901
Amortization of issuance costs	492	354	973	699
Total interest expense	922	5,295	1,834	10,462
0.25% Convertible Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Contractual interest expense	8	46	20	115
Amortization of debt discount		1,074		2,709
Amortization of issuance costs	18	80	44	203
Total interest expense	$ 26	$ 1,200	$ 64	$ 3,027