Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net loss	$ (7,731)	$ (4,092)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,487	1,542
Change in fair value of common stock warrant liability	3,304	(1,450)
Stock-based compensation	147	455
Amortization of operating lease right-of-use assets	563	477
Changes in operating assets and liabilities:
Accounts receivable	788	(770)
Unbilled accounts receivable	124	(55)
Inventories	699	135
Prepaid expenses and other current assets	(666)	(384)
Deferred revenues	116	290
Operating lease liabilities	(588)	(446)
Accounts payable, accrued expenses, and other current liabilities	63	(955)
Net cash used in operating activities	(1,694)	(5,253)
Cash flows from investing activities:
Purchase of equipment	(946)	(878)
Purchase of equipment Government grant	(582)
Net cash used in investing activities	(1,528)	(878)
Cash flows from financing activities:
(Repayments) borrowings under revolving line of credit, net	(2,401)	2,024
Proceeds from public offering, net	9,784	3,303
Proceeds from Government grant	2,404
Proceeds from Paycheck Protection Program loan	1,963
Proceeds from warrant exercise, net	40
Proceeds from exercise of stock options		8
Net cash provided by financing activities	11,790	5,335
Net increase in cash, cash equivalents, and restricted cash	8,568	(796)
Cash, cash equivalents, and restricted cash, beginning of period	3,515	3,359
Cash, cash equivalents, and restricted cash, end of period	12,083	2,563
Cash, cash equivalents, end of period	10,283	2,563
Restricted cash, end of period	1,800
Cash paid for interest	52	96
Cash paid for income taxes