Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (1,369)	$ (1,439)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	482	510
Change in fair value of common stock warrant liability	20	(794)
Stock-based compensation	43	193
Amortization of operating lease right-of-use assets	184	155
Changes in operating assets and liabilities:
Accounts receivable	229	(510)
Unbilled accounts receivable	(315)	155
Inventories	11	(245)
Prepaid expenses and other current assets	(214)	29
Deferred revenues	17	57
Operating lease liabilities	(192)	(159)
Accounts payable, accrued expenses, and other current liabilities	181	(263)
Net cash used in operating activities	(923)	(2,311)
Cash flows from investing activities:
Purchase of equipment	(306)	(188)
Net cash used in investing activities	(306)	(188)
Cash flows from financing activities:
Borrowings (repayments) under revolving line of credit, net	(700)	2,597
Proceeds from public offering, net	1,552
Net cash provided by financing activities	852	2,597
Net (decrease) increase in cash and cash equivalents	(377)	98
Cash and cash equivalents, beginning of period	3,515	3,359
Cash and cash equivalents, end of period	3,138	3,457
Cash paid for interest	22	32
Cash paid for income taxes