CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Operating activities:
Net loss	$ (16,054)	$ (7,075)
Adjustments to reconcile net loss to net cash flows from operating activities:
Depreciation and amortization expense	1,928	1,506
Stock-based compensation expense	20,339	17,885
Amortization of premiums and discounts on marketable securities	302	505
Non-cash lease cost	2,155	2,325
Other	16	5
Changes in operating assets and liabilities:
Inventory	(2,548)	(3,603)
Accounts receivable	3,773	2,772
Other current assets	(563)	1,039
Accounts payable	1,152	1,356
Accrued expenses	(1,912)	(216)
Operating lease liabilities	(1,977)	(1,644)
Net cash provided by operating activities	6,611	14,855
Investing activities:
Purchases of investments	(34,948)	(30,951)
Sales and maturities of investments	26,344	32,655
Expenditures for property and equipment	(5,062)	(4,461)
Net cash used in investing activities	(13,666)	(2,757)
Financing activities:
Net proceeds from common stock issuance	2,211	7,621
Payments on employee’s behalf for taxes related to vesting of restricted stock unit awards	(1,441)	(1,562)
Other	(18)	(16)
Net cash provided by financing activities	752	6,043
Net (decrease) increase in cash, cash equivalents, and restricted cash	(6,303)	18,141
Cash, cash equivalents, and restricted cash at beginning of period	68,541	33,831
Cash, cash equivalents, and restricted cash at end of period	62,238	51,972
Supplemental disclosure of cash flow information:
Additions to property and equipment included in accounts payable	869	630
Restricted stock held for employee tax remittance included in accounts payable	0	61
Reconciliation of amounts within the condensed consolidated balance sheets:
Cash and cash equivalents	56,054	51,761
Restricted cash	6,184	211
Total cash, cash equivalents, and restricted cash at end of period	$ 62,238	$ 51,972