Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 93,925	$ 34,479
Prepaid expenses	672	840
Total current assets	94,597	35,319
Property and equipment, net	14,154	14,044
Right of use and other assets	136	177
Total assets	108,887	49,540
Current liabilities:
Accounts payable	2,031	1,819
Accrued expenses	649	1,804
Lease liability, current portion	128	172
Total current liabilities	2,808	3,795
Long-term debt	15,472
Total liabilities	18,280	3,795
Stockholders' equity
Common stock, $.0001 par value, 150,000,000 shares authorized, 87,213,212 and 69,810,305 issued and outstanding at March 31, 2020 and December 31, 2019, respectively	9	7
Additional paid-in capital	358,851	306,108
Accumulated deficit	(268,253)	(260,370)
Total stockholders' equity	90,607	45,745
Total liabilities and stockholders' equity	$ 108,887	$ 49,540