Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net loss	$ (18,056)	$ (27,843)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	246	250
Write-off of intangibles, net of tax provision		4,575
Impairment of goodwill	0	5,029
Stock-based compensation	2,818	3,998
Non-cash rent expense	21	43
Non-cash interest expense	171	212
Non-cash debt issuance expense	12	16
Fair value adjustment on derivative liability	(34)	24
Loss on disposal of property and equipment		82
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(119)	983
Accounts payable	(290)	(346)
Accrued expenses	754	(312)
Net cash used in operating activities	(14,477)	(13,243)
Cash flows from investing activities:
Proceeds on sale of equipment		24
Purchases of property and equipment	(74)	(455)
Net cash used in investing activities	(74)	(431)
Cash flows from financing activities:
Proceeds from issuance of common stock and warrants, net	16,310
Proceeds from exercise of stock options	304
Principal payments term loan	(2,695)	(1,046)
Net cash provided by (used in) financing activities	13,919	(1,046)
Net decrease in cash and cash equivalents	(632)	(14,720)
Cash and cash equivalents - beginning of period	4,182	18,902
Cash and cash equivalents- end of period	$ 3,550	4,182
Supplemental disclosures of noncash financing and investing activities:
Fixed asset trade in value		60
Fixed asset purchases in accounts payable at year-end		$ 2