Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue	$ 12,839	$ 0
Operating expenses:
Royalty and direct contract acquisition costs	2,945
Research and development	19,415	41,759
General and administrative	10,816	12,508
Severance expense		1,636
Total operating expenses	33,176	55,903
Loss from operations	(20,337)	(55,903)
Other (expense) income:
Gain on extinguishment of debt		2
Interest expense related to amortization of debt issuance costs and discount	(1,656)	(1,618)
Interest expense on principal	(4,858)	(5,469)
Fair value adjustment related to derivative and warrant liability	1,998	5,976
Interest and other income, net	309	420
Total other (expense) income	(4,207)	(689)
Loss before income taxes	(24,544)	(56,592)
Income tax benefit	22	126
Net loss	$ (24,522)	$ (56,466)
Net loss per share of common stock:
Basic and diluted (in dollars per share)	$ (0.83)	$ (3.15)
Weighted average number of shares of common stock outstanding:
Basic and diluted (in shares)	29,654,968	17,930,023