Certain Balance Sheet Components - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Mar. 31, 2022
Other Liabilities Disclosure [Abstract]
Accrued sales discounts, rebates, and allowances	$ 36,858	$ 19,390
Accrued compensation-related expenses	23,516	26,389
Accrued R&D expenses	10,244	6,955
Accrued commercial expenses	5,287	7,196
Accrued royalties payable to Takeda	4,400	2,470
Accrued other expenses	3,288	3,309
Accrued professional fees	3,265	1,340
Accrued income tax payable	475	720
Deferred product revenue	0	825
Total accrued expenses and other current liabilities	$ 87,333	$ 68,594