Certain Balance Sheet Components - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Mar. 31, 2021
Other Liabilities Disclosure [Abstract]
Accrued compensation-related expenses	$ 26,389	$ 20,571
Accrued sales discounts, rebates, and allowances	19,390	1,315
Accrued R&D expenses	6,955	8,544
Accrued commercial expenses	7,196	7,770
Accrued other expenses	4,029	5,014
Accrued royalties payable to Takeda	2,470	301
Accrued professional fees	1,340	935
Deferred product revenue	825	162
Accrued expenses and other current liabilities	$ 68,594	$ 44,612