Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net loss	$ (48,661)	$ (32,231)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation expense	10,530	3,197
Change in fair value of derivative liability	0	(3,190)
Write-off of fixed assets	7	0
Allowance for doubtful accounts	4	(7)
Inventory write-downs	1,186	472
Depreciation and amortization expense	867	483
Amortization of debt discount and debt issuance costs	106	968
Write-off of deferred offering costs	0	3,030
Amortization of premiums and discounts on short-term marketable securities	59	(35)
Non-cash lease expense	2,360	1,467
Net changes in operating assets and liabilities:
Accounts receivable	(2,432)	1,457
Inventory	(6,458)	(5,047)
Prepaid expenses and other current assets	(1,214)	(1,756)
Other assets	(221)	65
Accounts payable	87	592
Accrued liabilities	4,800	1,019
Income taxes payable	21	(155)
Lease liabilities	(2,517)	(876)
Deferred tax liability	(6)	22
Deferred revenue	94	(108)
Net cash used in operating activities	(41,388)	(30,633)
Cash flows from investing activities
Purchases of investments	(52,584)	0
Maturities of investments	10,000	13,605
Purchases of property and equipment	(3,671)	(911)
Net cash provided by (used in) investing activities	(46,255)	12,694
Cash flows from financing activities
Proceeds from borrowing under term loans, net of payment of lender fees and costs	0	17,291
Repayment of term loans	0	(17,248)
Payment of Success Fee	0	(1,875)
Proceeds from the issuance of convertible note, net of payment of lender fees and costs (includes $0 and $0 from related party for the years ended December 31, 2021 and 2020, respectively)	0	32,950
Proceeds from Paycheck Protection Program loan	0	2,666
Repayment of Paycheck Protection Program loan	0	(2,666)
Debt issuance cost	(41)	(162)
Payments of deferred offering costs	0	(2,462)
Proceeds from exercise of warrants for Series C-1 convertible preferred stock	0	2,261
Proceeds from exercise of common stock options	1,871	2,705
Proceeds from issuance of common stock under the employee stock purchase plan	2,652	0
Proceeds from initial public offering, net of offering costs	0	201,392
Payments for the repurchase of early exercised common stock options	(26)	(21)
Net cash provided by financing activities	4,456	234,831
Effect of exchange rate changes on cash and cash equivalents	106	133
Net (decrease) increase in cash and cash equivalents	(83,081)	217,025
Cash and cash equivalents at beginning of year	231,792	14,767
Cash, cash equivalents and restricted cash at end of year	148,711	231,792
Reconciliation of cash, cash equivalents and restricted cash to consolidated balance sheets:
Cash and cash equivalents	148,480	231,561
Restricted cash	231	231
Cash, cash equivalents and restricted cash in consolidated balance sheets	148,711	231,792
Supplemental non-cash items:
Lapse (increase) in repurchase rights of common stock	204	(346)
Purchases of property and equipment in accounts payable and accrued liabilities	584	65
Issuance of derivative instrument related to convertible notes	0	3,900
Operating lease right of use assets obtained in exchange for new lease liabilities	1,460	3,935
Amount receivable from exercise of Options	10	0
Supplemental disclosure of cash flow information:
Cash paid for income taxes	322	259
Cash paid for interest	$ 722	$ 3,059