Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities
Net loss	$ (39,500)	$ (27,712)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	7,667	7,416
Depreciation and amortization	1,543	1,441
Amortization of deferred financing costs	367	355
Amortization of premium and accretion of discount on short-term investments, net	606	31
Non-cash operating lease cost	950	838
Allowance for inventory obsolescence and accounts receivable credit loss	610	951
Changes in operating assets and liabilities:
Accounts receivable	9,425	(2,462)
Inventory	(4,054)	(2,159)
Prepaid expenses and other assets	(3,050)	(3,559)
Accounts payable	3,924	943
Accrued liabilities	(3,372)	(1,060)
Accrued compensation and other employee benefits	(5,130)	(3,774)
Customer deposits	(16)	(299)
Deferred revenue and other liabilities	945	1,244
Operating lease liabilities	(1,168)	(1,050)
Net cash used in operating activities	(30,253)	(28,856)
Investing activities
Purchases of property and equipment	(3,002)	(2,672)
Purchase of internal-use software assets	(2,167)	0
Payments to Acquire Intangible Assets	(750)	0
Proceeds from maturity of short-term investments	37,424	15,362
Purchases of short-term investments	(10,800)	0
Net cash provided by investing activities	20,705	12,690
Financing activities
Tax withholdings related to net share settlements of restricted stock units	(1,504)	(2,585)
Proceeds from issuance of common stock for employee stock purchase plan	1,502	1,192
Proceeds from exercise of stock options	1,035	2,249
Repayment of finance lease obligations	(73)	0
Net cash provided by financing activities	960	856
Effect of exchange rate changes on cash and cash equivalents	(23)	(36)
Net decrease in cash and cash equivalents	(8,611)	(15,346)
Cash and cash equivalents
Beginning of period	107,068	411,848
End of period	$ 98,457	$ 396,502