Stock-based Compensation (Tables)

3 Months Ended

Mar. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

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

The weighted-average assumptions used in the Black-Scholes option-pricing model used to calculate the fair value of options granted during the three months ended March 31, 2017, were as follows:

	Employee			Non-Employee
Expected volatility		79.8% -83.7	%		N/A
Expected dividend yield		—			N/A
Expected term (in years)		3.25			N/A
Risk-free interest rate		1.87%-1.94	%		N/A

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

The table summarizes the stock option activity, for both plans, for the periods indicated as follows:

	Number of Options		Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term (years)		Aggregate Intrinsic Value(1)
Outstanding at December 31, 2016		1,477,300		1.61		5.8	$	9,662
Granted		25,000	$	8.04		5.0	$	-
Exercised		-	$	-		-	$	-
Forfeited		-	$	-		-	$	-
Expired		-	$	-		-	$	-
Outstanding at March 31, 2017		1,502,300		1.72		5.5	$	9,299
Exercisable at March 31, 2017		1,044,286	$	1.28		5.3	$	6,924

(1) The aggregate intrinsic value on the table was calculated based on the difference between the estimated fair value of the Company’s stock and the exercise price of the underlying option. The estimated stock values used in the calculation was $7.91 and $8.15 per share for the three months ended March 31, 2017 and the year ended December 31, 2016, respectively.

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]

The stock-based compensation expense was recorded as follows:

	Three Months Ended March 31,
	2017		2016
Research and development	$	94	$	87
General and administrative		967		1,044
Total stock-based compensation expense	$	1,061	$	1,131

Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]

The following table summarizes restricted stock unit activity for the three months ended March 31, 2017:

	Number of  Units			Weighted Average Grant-Date Fair Value Per Units
Outstanding as of December 31, 2016		455,430		$	0.76
Granted		40,000	(1)	$	8.35
Vested		(40,000	)	$	8.35
Forfeited		—		$	—
Outstanding as of March 31, 2017		455,430		$	0.76

(1) 40,000 restricted stock units were granted on March 27, 2017 with a weighted average grant date fair value of $8.35 and vested immediately.  The RSUs were settled for shares in April 2017.