CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities
Net loss	$ (35,923)	$ (26,223)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	11,258	8,287
Depreciation and amortization	1,505	845
Accretion of discount on marketable securities	515	721
Amortization of debt issuance costs	101	175
Loss on sale and disposal of property and equipment	105	125
Changes in operating assets and liabilities:
Accounts receivable	(720)	1,746
Inventory	(4,882)	(2,482)
Prepaid expenses and other assets	851	157
Accounts payable	936	554
Accrued liabilities and other	(2,099)	(1,415)
Net cash used in operating activities	(28,353)	(17,510)
Cash flows from investing activities
Maturities of marketable securities	48,000	56,977
Purchases of marketable securities	(55,356)	(43,337)
Purchases of property and equipment	(4,275)	(4,191)
Net cash (used in) provided by investing activities	(11,631)	9,449
Cash flows from financing activities
Proceeds from issuance of common stock under employee stock purchase plan	1,199	1,566
Proceeds from the exercise of stock options	199	1,251
Net cash provided by financing activities	1,398	2,817
Effect of exchange rate changes on cash and cash equivalents	(514)	(212)
Net decrease in cash and cash equivalents	(39,100)	(5,456)
Cash and cash equivalents at
Beginning of period	63,419	53,581
End of period	24,319	48,125
Supplemental disclosure of non-cash information
Vesting of early exercised stock options	0	18
Unpaid purchases of property and equipment	$ 1,593	$ 106