CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 76,963	$ 28,122
Prepaid expenses and other assets	11,194	12,027
Total current assets	88,157	40,149
Property and equipment, net	10,792	8,224
Operating lease right-of-use assets	1,815	1,927
Other assets	57	57
Total assets	100,821	50,357
Current liabilities:
Current portion of long-term debt	5,370	5,355
Accounts payable	5,898	3,674
Accrued expenses and other current liabilities	5,400	5,931
Total current liabilities	16,668	14,960
Long-term debt, net	5,425	6,773
Operating lease liabilities, net	1,428	1,548
Development derivative liability	68,260	51,719
Other long-term liabilities	629	559
Total liabilities	92,410	75,559
Commitments and contingencies (Note 8)
Stockholders’ equity (deficit):
Preferred stock, $0.001 par value; 10,000,000 shares authorized; zero shares issued and outstanding at March 31, 2021 and December 31, 2020	0	0
Common stock, $0.001 par value; 200,000,000 shares authorized; 47,982,000 shares issued and 47,952,033 shares outstanding at March 31, 2021; 29,471,854 shares issued and 29,441,887 shares outstanding at December 31, 2020	48	29
Treasury stock, at cost, 29,967 shares as of March 31, 2021 and December 31, 2020	(24)	(24)
Additional paid-in capital	296,468	235,516
Accumulated deficit	(288,081)	(260,723)
Total stockholders’ equity (deficit)	8,411	(25,202)
Total liabilities and stockholders' equity (deficit)	$ 100,821	$ 50,357