Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 256,672	$ 243,765
Prepaid expenses and other current assets	5,155	11,836
Total current assets	261,827	255,601
Property, plant and equipment, net	768	463
Operating lease right-of-use assets	939	933
Other long-term assets	381	181
Total assets	263,915	257,178
Current liabilities:
Accounts payable (including related party amounts of $112 and $200, respectively)	1,187	699
Accrued expenses (including related party amounts of $177 and $308, respectively)	3,004	2,319
Accrued interest	237	156
Operating lease liabilities, current	148	161
Warrant liabilities		413
Total current liabilities	4,576	3,748
Long-term debt, net of discount	45,913	22,777
Operating lease liabilities	606	635
Other long-term liabilities	4,125	2,063
Total liabilities	55,220	29,223
Commitments and contingencies (Note 4)
Stockholders’ equity:
Common stock, $0.0001 par value; authorized shares — 400,000,000; issued shares — 28,964,506; outstanding shares — 25,153,553 at March 31, 2020 and 24,728,258 at December 31, 2019, respectively;	2	2
Additional paid-in capital	485,253	484,372
Accumulated deficit	(276,560)	(256,419)
Total stockholders’ equity	208,695	227,955
Total liabilities and stockholders’ equity	$ 263,915	$ 257,178