CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Operating activities:
Net loss	$ (21,984)	$ (18,322)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation	2,973	2,076
Stock-based compensation	22,173	18,031
Accretion of discount or amortization of premium on investments	419	468
Amortization of debt issuance costs	806	188
Induced conversion expense related to convertible notes	2,232
Changes in operating assets and liabilities:
Accounts receivable	(4,679)	(973)
Inventory	(10,089)	12,265
Prepaid expenses and other assets	1,463	(186)
Accounts payable	(2,201)	(3,053)
Accrued compensation and employee related benefits	(437)	422
Accrued and other liabilities	366	364
Operating lease right-of-use assets	1,623	1,458
Operating lease liabilities	(2,034)	(1,834)
Restructuring liabilities	(472)	630
Deferred revenue	2,202	(6,553)
Net cash provided by (used in) operating activities	(7,639)	4,981
Investing activities:
Purchases of investments	(115,697)	(19,825)
Proceeds from maturities of investments	46,805	41,000
Purchases of property and equipment	(3,724)	(7,858)
Net cash provided by (used in) investing activities	(72,616)	13,317
Financing activities:
Principal payments on finance lease obligations		(2)
Proceeds from exercise of stock options and employee stock purchase plan	6,496	9,243
Net cash provided by (used in) financing activities	(11,068)	9,241
Net increase (decrease) in cash and cash equivalents	(91,323)	27,539
Cash and cash equivalents
Beginning of period	123,903	23,636
End of period	32,580	51,175
Supplemental disclosure of cashflow information:
Cash paid for interest	1,803	863
Purchases of property and equipment not yet paid	891	$ 5,069
2019 Notes
Financing activities:
Payment of 2019 Notes	$ (17,564)