Product Revenues, Accounts Receivable, and Reserves for Product Sales - Summary of Product Revenue Allowance and Reserve Categories (Detail) - USD ($) $ in Thousands	3 Months Ended
Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024
Fees And Patient Assistance [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	$ 10,460	$ 9,221	$ 11,589	$ 5,930	$ 5,671	$ 5,674
Provision related to sales in the current period	12,695	12,138	10,277	11,455	10,025	9,575
Adjustments related to prior period sales	366	(66)	439	2,332	(131)	146
Credits and payments made	(12,436)	(10,833)	(13,084)	(12,078)	(9,635)	(9,724)
Ending balance	11,085	10,460	9,221	7,639	5,930	5,671
Government and Other Rebates [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	30,577	27,192	31,533	15,589	12,098	8,898
Provision related to sales in the current period	38,426	30,823	24,139	25,364	17,777	13,125
Adjustments related to prior period sales	(12)	185	(13)	420	354	(19)
Credits and payments made	(34,730)	(27,623)	(28,467)	(17,695)	(14,640)	(9,906)
Ending balance	34,261	30,577	27,192	23,678	15,589	12,098
Returns [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	3,485	2,491	2,023	1,183	1,453	2,053
Provision related to sales in the current period	1,152	1,083	976	1,380	1,039	1,355
Adjustments related to prior period sales	(211)	852	(382)	0	(983)	(96)
Credits and payments made	(2,324)	(941)	(126)	(979)	(326)	(1,859)
Ending balance	2,102	3,485	2,491	1,584	1,183	1,453
Product Revenue Allowance and Reserves [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	44,522	38,904	45,145	22,702	19,222	16,625
Provision related to sales in the current period	52,273	44,044	35,392	38,199	28,841	24,055
Adjustments related to prior period sales	143	971	44	2,752	(760)	31
Credits and payments made	(49,490)	(39,397)	(41,677)	(30,752)	(24,601)	(21,489)
Ending balance	$ 47,448	$ 44,522	$ 38,904	$ 32,901	$ 22,702	$ 19,222