Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2016

Fair Value Measurements

Schedule of financial assets and liabilities at fair value

	Level 1		Level 2		Level 3		Total
	(in thousands)
At March 31, 2016
Assets:
Cash and cash equivalents	$	2,109	$	—	$	—	$	2,109
Trade accounts receivable		530		—		—		530
Short-term investments		154		—		—		154
	$	2,793	$	—	$	—	$	2,793
Liabilities:
Warrant liability	$	—	$	—	$	1,390	$	1,390
Derivative liability		—		—		687		687
	$	—	$	—	$	2,077	$	2,077
At December 31, 2015
Assets:
Cash and cash equivalents	$	4,077	$	—	$	—	$	4,077
Trade accounts receivable		546		—		—		546
Short-term investments		72		—		—		72
	$	4,695	$	—	$	—	$	4,695
Liabilities:
Warrant liability	$	—	$	—	$	210	$	210
Derivative liability		—		—		488		488
	$	—	$	—	$	698	$	698

Schedule of significant inputs to the valuation model

	March 31,		December 31,
	2016		2015
Company's ending stock price	$	0.45	$	0.20
Company's stock volatility		105%		85%
Applicable risk free interest rate		0.94%		1.48%

Summary of change in fair value of the warrant liability

	Fair Value Measurements
	Using Significant Unobservable
	Inputs (level 3)
	Warrant Liabilities		Derivative  Liability
	(in thousands)
Ending balance at December 31, 2015	$	210	$	488
Conversion of Sentient Loan (see Note 11)		—		(449)
Change in estimated fair value		1,180		648
Ending balance at March 31, 2016	$	1,390	$	687