Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Operating activities:
Net loss	$ (2,740)	$ (6,661)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	779	922
Amortization of debt discounts and financing issuance costs	239	459
Restructuring reserve adjustment		(123)
Change in fair value of warrant liability	812
Loss on debt extinguishment	203	405
Provision for adjustments to accounts receivable and doubtful accounts	(82)	182
Provision for excess and obsolete inventory	(16)
Loss (gain) on disposal of fixed assets	7	(6)
Non-cash compensation related to stock options and restricted stock	935	1,171
Deferred income taxes	213	(585)
Change in operating accounts:
Accounts receivable	(1,903)	(365)
Prepaid expenses and other assets	(197)	154
Accounts payable and accrued liabilities	(1,079)	(2,947)
Deferred revenue	(45)	(25)
Net cash used in operating activities	(2,874)	(7,419)
Investing activities:
Capital expenditures	(173)	(77)
Net cash used in investing activities	(173)	(77)
Financing activities:
Cash received from issuance of common stock and warrants, net of offering costs	17,600	2,056
Cash received from issuance of preferred stock, net of offering costs		2,413
Cash received from (repayments of) short-term secured promissory notes	(1,000)	1,800
Cash received from (repayments of) related-party notes payable	(1,200)	1,200
Repayments of notes payable	(2,000)
Cash received from stock sale for employee stock purchase plan	5	3
Preferred stock dividends	(404)
Net cash provided by financing activities	13,001	7,472
Net increase (decrease) in cash and cash equivalents	9,954	(24)
Cash and cash equivalents, beginning of period	2,205	2,229
Cash and cash equivalents, end of period	12,159	2,205
Supplemental disclosures of cash flow information:
Cash paid for income taxes	2	15
Cash paid for interest expense	386	662
Non-cash investing and financing activities:
Change in unrealized loss on short-term investments	(1)
Issuance of common stock warrants in connection with stock offering	10,792	64
Reclassification of warrants from liabilities to equity	7,604
Conversion of preferred stock to common stock	$ 4
Issuance of preferred stock in settlement of senior subordinated debt		$ 2,800