Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash Flows From Operating Activities
Net loss	$ (21,803)	$ (13,828)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation of leasehold improvements and equipment	679	652
Amortization of intangibles	174	182
Amortization of right of use assets	385	284
Share-based compensation expense	4,722	5,158
Change in allowance for doubtful trade receivables	(152)	(2,737)
Non-cash financing costs	87	75
Changes in operating assets and liabilities:
Trade receivables	(2,448)	1,698
Inventories	(992)	504
Implementation costs for cloud computing arrangement	(150)	0
Prepaid expenses and other assets	(608)	(185)
Accounts payable	1,359	(2,745)
Accrued expenses	198	757
Deferred revenue	(95)	(53)
Customer deposits and other	(103)	56
Principal payments on operating leases	(472)	(440)
Net cash used in operating activities	(19,219)	(10,622)
Cash Flows From Investing Activities
Purchases of leasehold improvements and equipment	(407)	(147)
Purchases of intangible assets	0	(18)
Investment in other long-term assets	0	(16)
Net cash used in investing activities	(407)	(181)
Cash Flows From Financing Activities
Proceeds from issuance of common stock, net	26,740	4,856
Proceeds from exercise of stock options	9,365	2,859
Payment of debt issuance costs	(47)	(30)
Principal payments on finance leases	(27)	(216)
Net cash provided by financing activities	36,031	7,469
Net increase in cash	16,405	(3,334)
Cash, including restricted cash of $0.2 million for both 2021 and 2020 - beginning of period	16,697	18,812
Cash, including restricted cash of $0.2 million for both 2021 and 2020 - end of period	33,102	15,478
Supplemental Disclosures of Cash Flow Information
Cash payments for interest on finance leases	1	11
Supplemental Schedule of Noncash Operating Activity
Right-of-use assets and operating lease obligations incurred for entering into lease amendment	2,209	716
Supplemental Schedule of Noncash Investing Activity
Financing lease obligation incurred for purchase of computer equipment and software	$ 0	$ 47