Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2020

Schedule of assets and liabilities measured and recorded in financial statements at fair value on a recurring basis

	March 31, 2020
(In thousands)	Total		Level 1		Level 2		Level 3
Assets
Cash	$	250	$	250	$	—	$	—
Cash equivalents  – money market funds		26,860		26,860		—		—
Cash equivalents – commercial paper		799		—		799		—
Short-term investments – commercial paper		5,578		—		5,578		—
Total assets	$	33,487	$	27,110	$	6,377	$	—
Liabilities
Warrant liability	$	2,140	$	—	$	—	$	2,140
Future tranche right liability		25,725		—		—		25,725
Total liabilities	$	27,865	$	—	$	—	$	27,865
	December 31, 2019
(In thousands)	Total		Level 1		Level 2		Level 3
Assets
Cash	$	250	$	250	$	—	$	—
Cash equivalents  – money market funds		39,769		39,769		—		—
Short-term investments – commercial paper		2,774		—		2,774		—
Total assets	$	42,793	$	40,019	$	2,774	$	—
Liabilities
Warrant liability	$	3,241	$	—	$	—	$	3,241
Future tranche right liability		46,436		—		—		46,436
Total liabilities	$	49,677	$	—	$	—	$	49,677

Schedule of reconciliation measured at fair value on a recurring basis using unobservable inputs

			Future
	Warrant		Tranche Right
(In thousands)	Liability		Liability
Balance, December 31, 2019	$	3,241	$	46,436
Change in the fair value of liability		(1,101)		(20,711)
Balance, March 31, 2020	$	2,140	$	25,725

Warrant liability

Schedule of assumptions used in determining fair value

	March 31,		December 31,
	2020		2019
Risk-free interest rate		0.53%		1.79%
Expected dividend yield		—		—
Expected term (years)		6.73		6.98
Expected volatility		80%		80%
Exercise price (per share)	$	1.52	$	1.52

Future tranche right liability

Schedule of assumptions used in determining fair value

	March 31,		December 31,
	2020		2019
Risk-free interest rate for warrants		0.53%		1.79%
Risk-free interest rate for preferred stock		0.59% - 0.65%		1.84% - 1.88%
Expected dividend yield		—		—
Expected term (years) of call option on preferred stock		0.91 - 1.91		1.16 - 2.16
Expected term (years) of warrants		7.91 - 8.91		8.16 - 9.16
Expected volatility		80%		80%
Exercise price (per share) for common stock equivalent for preferred stock and warrant	$	1.52 - 1.82	$	1.52 - 1.82