CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS Unaudited - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net loss	$ (31,988)	$ (45,913)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,435	1,248
Amortization of investment discount	79	97
Equity-based compensation	6,950	15,429
Amortization of debt discount and issuance costs	284	6,079
Loss (gain) on disposal of property and equipment	283	(100)
Unrealized loss on equity investments	157	0
Gain on extinguishment of debt	(3,565)	0
(Increase) decrease in assets:
Contributions to deferred compensation plan	(110)	(236)
Accounts receivable	(615)	(564)
Inventory	(416)	(524)
Prepaid expense and other	(719)	60
Increase (decrease) in liabilities:
Accounts payable	658	564
Accrued liabilities	2,288	736
Accrued interest	(159)	45
Deferred revenue and income	(116)	(94)
Deferred compensation	(51)	245
Net cash used in operating activities	(25,605)	(22,928)
Cash flows from investing activities:
Purchases of equipment	(447)	(29)
Purchase of marketable securities	(27,504)	(15,699)
Maturities of marketable securities	18,738	23,993
Net cash (used in) provided by investing activities	(9,213)	8,265
Cash flows from financing activities:
Proceeds from issuance of common stock	0	22,122
Payments on finance leases	(424)	0
Proceeds from exercise of options	7	1,222
Proceeds from issuance of common stocks under employee purchase plan	137	161
Net cash (used in) provided by financing activities	(280)	23,505
Effect of exchange rate on cash	(219)	(43)
(Decrease) increase in cash and cash equivalents	(35,317)	8,799
Cash and cash equivalents, beginning of period	39,898	35,781
Cash and cash equivalents, end of period	4,581	44,580
Non-cash investing activities:
Net transfer of instruments from inventory to property and equipment	202	500
Supplemental cash flow information:
Interest paid	1,506	2,144
Extinguishment of Convertible Senior Notes through issuance of common stock	$ 10,180	$ 0