Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (30,187)	$ (42,854)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	5,381	7,258
Depreciation and amortization	2,652	3,074
Impairment of goodwill and intangible assets	630
Amortization of intangible assets	190	189
Amortization of debt discount		19
Bad debt expense	75	148
Inventory write-off	747
Gain on extinguishment of debt – PPP loan	(3,612)
Change in fair value of common stock warrant liability	(4,995)	(2,914)
Inducement loss on sale of liability classified warrants	5,197
Loss on restructuring and other charges	321
Loss on sale of property and equipment and ROU assets	12	2,806
Loss on abandonment of property and equipment	209
Other non-cash adjustments	(45)	(21)
Changes in operating assets and liabilities:
Accounts receivable	2,766	(2,236)
Inventory	136	(631)
Prepaid expenses and other current assets	(603)	272
Operating lease right-of-use assets	1,318	1,700
Other assets/liabilities, net	(248)	(200)
Accounts payable and accrued expenses	(1,047)	(2,761)
Other current liabilities	(29)	35
Deferred revenue	(94)	70
Operating lease liabilities	(1,404)	(1,708)
Net cash used in operating activities	(22,630)	(37,754)
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES
Purchase of property and equipment	(123)	(1,339)
Proceeds from sale of property and equipment	27
Purchase of available-for-sale securities		(14,144)
Proceeds from maturities of available-for-sale securities		16,945
Proceeds from sale of available-for-sale securities		16,171
Net cash provided by/(used in) investing activities	(96)	17,633
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from term note payable and financing arrangements	1,028	4,629
Principal payments on term note payable and financing arrangements	(1,054)	(1,675)
Principal payments on financing leases	(555)	(508)
Net proceeds from the sale of common stock, warrants and pre-funded warrants	9,884	32,020
Proceeds from the sale of new warrants	1,002
Proceeds from warrants exercised	6,671	1,008
Proceeds from pre-funded warrants exercised	8
Cash paid for tax withholdings related to net share settlement	(463)	(155)
Proceeds from stock options exercised	3	31
Proceeds from ESPP purchase	55	75
Net cash provided by financing activities	16,579	35,425
Net increase (decrease) in cash and cash equivalents	(6,147)	15,304
Cash and cash equivalents - beginning of period	25,522	10,218
Cash and cash equivalents - end of period	19,375	25,522
Supplemental cash flow information:
Cash paid for interest	118	187
Supplemental schedule of non-cash investing and financing activities:
Fair value of placement agent warrants issued in connection with offering	838
Reclassification of warrant liability to stockholders’ equity upon exercise of warrant	8,964	8,265
Allocation of proceeds from sale of common stock and warrants to warrant liability	8,629	17,154
Unpaid liability for acquisition of property and equipment	21	87
Right-of-use asset obtained in exchange for new lease liability	42	82
Accrued offering costs	400
Reclassification of equipment to assets held for sale	$ 441