Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating activities:
Net loss	$ (27,039)	$ (18,864)
Adjustments to reconcile net loss to net cash used for operating activities:
Depreciation, amortization, and impairment	1,497	1,684
Share-based compensation	3,228	3,625
Amortization of debt issuance costs and discounts	2,388	1,167
Interest expense related to the sale of future revenue, net	6,729	0
Other, net	(125)	(139)
Changes in operating assets and liabilities:
Trade and other receivables, net	(5,392)	354
Inventories, net	(378)	(314)
Prepaid expenses and other assets	2,532	(6,426)
Accounts payable	1,011	(3,388)
Accrued expenses and other liabilities	(2,971)	(849)
Deferred revenue	2,667	(484)
Net cash used for operating activities	(15,853)	(23,634)
Investing activities:
Capital expenditures	(297)	(243)
Net cash used for investing activities	(297)	(243)
Financing activities:
Proceeds from issuance of common stock, net	18,505	0
Proceeds from shares issued under employee stock purchase plan	76	62
Payments for taxes on share-based compensation	(4)	(89)
Net cash provided by/(used for) financing activities	18,577	(27)
Net increase (decrease) in cash and cash equivalents	2,427	(23,904)
Cash and cash equivalents at beginning of period	31,807	49,326
Cash and cash equivalents at end of period	34,234	25,422
Supplemental disclosures of cash flow information:
Cash payments for interest	$ 3,219	$ 4,375