Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2020

Fair Value Disclosures [Abstract]

Schedule of fair value measurements by level

The following tables summarize fair value measurements by level as of March 31, 2020 and December 31, 2019, respectively, for assets and liabilities measured at fair value on a recurring basis:

	Balance as of March 31, 2020
(in thousands)	Level I		Level II		Level III		Total
Letter of credit (1)	$	408	$	—	$	—	$	408
Total assets	$	408	$	—	$	—	$	408
Warrant liabilities	$	—	$	—	$	627	$	627
Total liabilities	$	—	$	—	$	627	$	627

(1) $408,000 is included in restricted cash, long-term on the condensed consolidated balance sheet as of March 31, 2020.

	Balance as of December 31, 2019
(in thousands)	Level I		Level II		Level III		Total
Letter of credit (2)	$	408	$	—	$	—	$	408
Total assets	$	408	$	—	$	—	$	408
Warrant liabilities	$	—	$	—	$	691	$	691
Total liabilities	$	—	$	—	$	691	$	691

(2) $408,000 is included in restricted cash, long term on the condensed consolidated balance sheet as of December 31st, 2019.

Schedule of fair value measurements using significant Level III inputs

The fair value measurements using significant Level III inputs, and changes therein, for the quarter ended March 31, 2020 are as follows:

(in thousands)	Level III Warrant Liabilities
Balance as of December 31, 2019	$	691
Issuance of new warrant liability	—
Change in fair value of warrant liability	(64)
Balance as of March 31, 2020	$	627

Schedule of warranty liability assumptions

The assumptions used in the Black-Scholes option-pricing model remain unchanged and are determined as follows:

	March 31, 2020
Volatility	98.01	%
Risk-free interest rate	1.58	%
Expected life (in years)	7
Dividend yield	0 %

The assumptions used in the Black-Scholes option-pricing model are determined as follows:

	March 31, 2020		December 31, 2019
Volatility	98.04	%	98.04	%
Risk-free interest rate	0.55	%	1.81	%
Weighted average expected life (in years)	6.1		6.25
Dividend yield	—	%	—	%