Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
CURRENT ASSETS:
Cash and cash equivalents	$ 104,055	$ 147,528
Prepaid expenses and other current assets	2,415	2,369
Total current assets	106,470	149,897
Property and equipment, net	52	113
Operating lease right-of-use asset	318	589
Other assets	647	729
TOTAL ASSETS	107,487	151,328
CURRENT LIABILITIES:
Accrued and other liabilities	7,148	7,170
Accounts payable	2,205	1,019
Warrant liabilities		45,935
Securities issuance obligation		10,485
Total current liabilities	9,353	64,609
Operating lease liability	175	374
TOTAL LIABILITIES	9,528	64,983
Commitments and Contingencies (Note 8)
STOCKHOLDERS’ EQUITY:
Preferred stock, $0.001 par value; 10,000,000 shares authorized as of December 31, 2020 and December 31, 2019; nil shares issued and outstanding as of December 31, 2020 and 103,000 shares of Series A convertible voting preferred stock issued and outstanding as of December 31, 2019		1
Common stock, $0.001 par value; 500,000,000 shares authorized as of December 31, 2020 and December 31, 2019; 11,128,484 and 1,867,176 shares issued and outstanding as of December 31, 2020 and 2019	11	74
Additional paid-in capital	944,537	851,957
Accumulated deficit	(846,589)	(765,687)
TOTAL STOCKHOLDERS’ EQUITY	97,959	86,345
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 107,487	$ 151,328