Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net loss	$ (58,550)	$ (71,961)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	8,402	9,621
Amortization and impairment of internal-use software	1,106	1,078
Stock-based compensation expense	20,064	22,227
Change in fair value of warrant liabilities	(29,294)	0
Loss (gain) on disposal of property and equipment	42	(5)
Gain on lease termination	(15)	(876)
Changes in operating assets and liabilities:
Accounts receivable (related party amounts of $(25,000) and $(25,000) for the six months ended September 30, 2021 and 2020, respectively)	(24,226)	(20,242)
Inventories	(11,494)	1,651
Deferred cost of revenue	(44)	1,772
Prepaid expenses and other current assets	(5,360)	5,208
Operating lease right-of-use assets	3,496	6,742
Other assets	(654)	389
Accounts payable (related party amounts of $(4,422) and $(1,617) for the six months ended September 30, 2021 and 2020, respectively)	(997)	(4,201)
Accrued expenses and other current liabilities (related party amounts of $5,545 and $(790) for the six months ended September 30, 2021 and 2020, respectively)	(2,276)	(1,061)
Deferred revenue (related party amounts of $3,788 and $3,333 for the six months ended September 30, 2021 and 2020, respectively)	(3,574)	(7,934)
Operating lease liabilities	(3,696)	(4,870)
Other liabilities	45	43
Net cash used in operating activities	(107,025)	(62,419)
Cash flows from investing activities:
Purchases of property and equipment	(1,810)	(3,627)
Prepayments for intangible assets	(5,500)
Proceeds from sale of property and equipment	1	612
Capitalized internal-use software costs	(1,807)	(1,988)
Net cash used in investing activities	(9,116)	(5,003)
Cash flows from financing activities:
Proceeds from exercise of stock options (related party amounts of nil and $34,710 for the six months ended September 30, 2021 and 2020, respectively)	5,624	36,587
Payments of deferred offering costs	(30,642)
Proceeds from issuance of common stock upon Merger	309,720
Net cash provided by financing activities	534,702	36,587
Net increase (decrease) in cash and restricted cash	418,561	(30,835)
Cash and restricted cash—beginning of period	290,862	216,316
Cash and restricted cash—end of period	709,423	185,481
Supplemental disclosures of non-cash investing and financing activities:
Purchases of property and equipment during the period included in accounts payable and accrued expenses	34	78
Stock-based compensation capitalized for internal-use software costs	437	312
Reclassification of deferred offering costs	3,971	0
Vesting of related party early exercised stock options	0	8,482
Assumption of merger warrants liability	75,415	0
Conversion of redeemable convertible preferred stock to common stock	837,351	0
Reconciliation of cash and restricted cash within the consolidated balance sheets to the amounts shown in the consolidated statements of cash flows above:
Cash	701,050	177,108
Restricted cash, current	1,399	1,399
Restricted cash, noncurrent	6,974	6,974
Total cash and restricted cash	709,423	185,481
PIPE [Member]
Cash flows from financing activities:
Proceeds from issuance of common stock upon Merger	$ 250,000