Stock-Based Compensation (Tables) - Equity Incentive Plan 2013 [Member]

6 Months Ended

Jun. 30, 2016

Stock Based Compensation [Line Items]

Schedule of Share-based Compensation, Activity [Table Text Block]

The Company has granted options to purchase common stock and restricted stock units under the Plan. Stock option activity during the six months ended June 30, 2016 was as follows:

	Amount		Weighted-average exercise price
Outstanding at December 31, 2015		3,253,118	$	3.29
Granted		822,500		1.64
Canceled		(275,929)		3.65
Outstanding at June 30, 2016		3,799,689	$	2.91

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

The weighted average assumptions for valuing those options granted were as follows:

 

Expected volatility	74.29	%
Expected dividends	0.00	%
Expected term in years	6.11
Risk-free rate	1.53	%

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

The Company recorded total stock-based compensation during the three and six months ended June 30 as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2016		2015		2016		2015
	(in thousands)				(in thousands)
Research and development	$	180	$	142	$	337	$	373
General and administrative		138		2,303		328		2,810
Total stock-based compensation	$	318	$	2,445	$	665	$	3,183