Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

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

Schedule of fair value of options granted

The weighted-average assumptions used in the Black-Scholes option-pricing model used to calculate the fair value of options granted during the year ended December 31, 2015, were as follows:

	Employee			Non-Employee
Expected volatility		66.4	%		76.6	%
Expected dividend yield		—			—
Expected term (in years)		4.0			5.0
Risk-free interest rate		1.3	%		1.7	%

The weighted-average assumptions used in the Black-Scholes option-pricing model used to calculate the fair value of options granted during the year ended December 31, 2016, were as follows:

	Employee			Non-Employee
Expected volatility		82.1	%		N/A
Expected dividend yield		—			N/A
Expected term (in years)		3.25			N/A
Risk-free interest rate		1.83	%		N/A

Schedule of stock option activity

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, 2014		255,509	$	2.35		3.9	$	3,230
Granted		2,477,255	$	0.50		7.1
Exercised		384,206	$	0.05
Forfeited		210,876	$	0.50
Expired		13,348	$	15.00
Outstanding at December 31, 2015		2,124,334	$	0.50		6.4	$	4,249
Granted		200,000	$	7.98		5.0	$	34
Exercised		621,602	$	0.73
Forfeited		210,849	$	0.50
Expired		14,583	$	15.00
Outstanding at December 31, 2016		1,477,300		1.61		5.8	$	9,662
Exercisable at December 31, 2016		999,310	$	1.00		5.6	$	7,145

(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 $8.15 and $2.50 per share for each of the years ended December 31, 2016 and 2015 respectively.

Schedule of stock-based compensation expense

The stock-based compensation expense was recorded as follows:

	Year Ended December 31,
	2016		2015
Research and development	$	403	$	4,931
General and administrative		2,966		6,331
Total stock-based compensation expense	$	3,369	$	11,262

Schedule of summarizes restricted stock unit activity

The following table summarizes restricted stock unit activity for the years ended December 31, 2016 and 2015:

	Number of  Units			Weighted Average Grant-Date Fair Value Per Units
Outstanding as of December 31, 2014		—		$	—
Granted		—		$	—
Vested		—		$	—
Forfeited		—		$	—
Outstanding as of December 31, 2015		—		$	—
Granted		474,720	(1)	$	1.57
Vested		(19,290	)	$	8.10
Forfeited		—		$	—
Outstanding as of December 31, 2016		455,430		$	0.76

(1) 440,000 restricted stock units were granted and issued on September 30^th with a weighted average grant date fair value of $0.50 and vest 1/3 on the first anniversary of grant and the remaining balance quarterly over the subsequent 8 quarters. 19,290 restricted stock units were granted on December 19, 2016 with a weighted average grant date fair value of $8.10 and vested immediately. An additional 15,430 restricted stock units were granted on December 19, 2016 and fully vest on the first anniversary of grant. The Company accounts for the restricted stock units as equity-settled awards in accordance with ASC 718. The total fair value of restricted stock units vested during the years ended December 31, 2016 and 2015 was $156 and $0.00, respectively.