CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities:
Net loss	$ (10,461)	$ (9,416)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation	1,508	1,040
Stock-based compensation	11,314	7,449
Accretion of discount or amortization of premium on investments	301	218
Amortization of debt issuance costs	403	94
Changes in operating assets and liabilities:
Accounts receivable	(3,084)	1,498
Inventory	(9,603)	8,262
Prepaid expenses and other assets	(2,142)	880
Accounts payable	(2,768)	(2,137)
Accrued compensation and employee related benefits	(1,775)	345
Accrued and other liabilities	1,279	722
Operating lease right-of-use assets	804	723
Operating lease liabilities	(1,008)	(911)
Restructuring liabilities	(37)	1,235
Deferred revenue	433	(633)
Net cash provided by (used in) operating activities	(14,836)	9,369
Investing activities:
Purchases of investments	(67,085)	(12,333)
Proceeds from maturities of investments	20,000	25,000
Purchases of property and equipment	(3,050)	(4,398)
Net cash provided by (used in) investing activities	(50,135)	8,269
Financing activities:
Principal payments on finance lease obligations		(2)
Proceeds from exercise of stock options and employee stock purchase plan	4,611	8,524
Net cash provided by financing activities	4,611	8,522
Net increase (decrease) in cash and cash equivalents	(60,360)	26,160
Cash and cash equivalents
Beginning of period	123,903	23,636
End of period	63,543	49,796
Supplemental disclosure of cashflow information:
Purchases of property and equipment not yet paid	$ 508	$ 1,984