Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
CURRENT ASSETS:
Cash and cash equivalents	$ 107,658	$ 104,055
Prepaid expenses and other current assets	2,010	2,415
Total current assets	109,668	106,470
Property and equipment, net	42	52
Operating lease right-of-use asset	281	318
Other assets	572	647
TOTAL ASSETS	110,563	107,487
CURRENT LIABILITIES:
Accrued and other liabilities	6,364	7,148
Accounts payable	2,522	2,205
Total current liabilities	8,886	9,353
Operating lease liability	122	175
TOTAL LIABILITIES	9,008	9,528
Commitments and Contingencies (Note 7)
STOCKHOLDERS’ EQUITY:
Preferred stock, $0.001 par value; 10,000,000 shares authorized as of March 31, 2021 and December 31, 2020; nil shares issued and outstanding as of March 31, 2021 and December 31, 2020
Common stock, $0.001 par value; 500,000,000 shares authorized as of March 31, 2021 and December 31, 2020; 12,349,961 and 11,128,484 shares issued and outstanding as of March 31, 2021 and December 31, 2020	12	11
Additional paid-in capital	968,047	944,537
Accumulated deficit	(866,504)	(846,589)
TOTAL STOCKHOLDERS’ EQUITY	101,555	97,959
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 110,563	$ 107,487