Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2020

Share-based Payment Arrangement [Abstract]

Schedule of fair value of options granted

	Employee			Non-Employee
Expected volatility		88.1	%		N/A
Expected dividend yield		—			N/A
Expected term (in years)		5			N/A
Risk-free interest rate		0.26	%		N/A

Schedule of stock option activity

	Number of Options			Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term (years)		Aggregate Intrinsic Value (1)
Outstanding at December 31, 2019		136,489		$	28.00		3.9	$	—
Granted		25,000		$	2.44		4.8	$	—
Exercised		—		$	—		—	$	—
Forfeited		(6,000	)	$	—		—	$	—
Expired		—		$	—		—	$	—
Outstanding at June 30, 2020		155,489		$	24.83		3.9	$	—
Exercisable at June 30, 2020		99,573		$	28.22		2.5	$	—

(1) The aggregate intrinsic value in the table was calculated based on the difference between the estimated fair market value of the Company's stock and the exercise price of the underlying options. The estimated stock values used in the calculation were $2.00 and $11.00 per share for the six months ended June 30, 2020 and the year ended December 31, 2019, respectively.

Schedule of summarizes restricted stock unit activity

	Number of Units			Weighted Average Grant-Date Fair Value Per Unit
Outstanding as of December 31, 2019		5,877		$	30.28
Granted		—		$	—
Vested		(4,543	)	$	1.42
Forfeited		—		$	—
Outstanding as of June 30, 2020		1,334		$	1.80

Schedule of stock-based compensation expense

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
Research and development	$	2	$	1	$	5	$	10
General and administrative		138		218		286		461
Total stock-based compensation expense	$	140	$	219	$	291	$	471