Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities:
Net loss	$ (66,858)	$ (83,251)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Share-based compensation	21,423	23,125
Depreciation	670	716
Non-cash interest expense	568	1,210
Amortization of operating lease right-of-use assets	935	820
Changes in operating assets and liabilities:
Accounts receivable	(10,466)	(10,832)
Inventories	(14,984)	(3,530)
Prepaid expenses and other current assets	(9,328)	(4,414)
Amount due from related party	(363)	0
Other assets	8,399	1,798
Accounts payable	(4,083)	(9,519)
Accrued expenses and other current liabilities	15,487	1,722
Deferred revenue	20,282	28,652
Amounts due to Pfizer	6,376	18,003
Cost share advance from Pfizer	(34,386)	(38,304)
Operating lease liabilities	(1,027)	(869)
Amounts due to related parties	458	(209)
Other liabilities	12	(1,696)
Net cash used in operating activities	(66,885)	(76,578)
Cash flows from investing activities:
Purchases of marketable securities	(24,647)	(94,448)
Maturities of marketable securities	22,800	7,035
Purchases of property and equipment	(386)	(361)
Net cash used in investing activities	(2,233)	(87,774)
Cash flows from financing activities:
Proceeds from stock option exercises	5,142	15,135
Net cash provided by financing activities	5,142	15,135
Net change in cash, cash equivalents and restricted cash	(63,976)	(149,217)
Cash, cash equivalents and restricted cash, beginning of period	416,804	677,480
Cash, cash equivalents and restricted cash, end of period	352,828	528,263
Supplemental Disclosure of Non-Cash Financing and Investing Information:
Change in fair value of share-based awards recorded to additional paid-in capital	0	2,292
Equipment purchases included in accounts payable	48	352
Reclassification of share-based compensation liabilities to additional paid-in capital upon settlement of awards	0	18,159
Stock options exercised receivable, included in prepaid expenses and other current assets	$ 42	$ 162