CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 19,645	$ 19,859
Short-term investments	41,302	51,358
Prepaid expenses and other current assets	4,329	6,175
Total current assets	65,276	77,392
Property and equipment, net	509	527
Acquired intangible asset	2,258	2,258
Goodwill	881	881
Right-of-use lease assets	229	296
Other assets	1,946	1,957
Total assets	71,099	83,311
Current liabilities:
Accounts payable	4,131	5,044
Accrued expenses	6,566	7,633
Lease liabilities	234	258
Total current liabilities	10,931	12,935
Royalty purchase liability	130,366	128,063
Lease liabilities, net of current portion		44
Deferred tax liability	273	273
Total liabilities	141,570	141,315
Stockholders' deficit:
Preferred stock, $0.001 par value: 10,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.001 par value: 200,000,000 shares authorized; 26,819,421 and 26,458,767 shares issued and outstanding at March 31, 2022 and December 31, 2021, respectively	27	26
Additional paid-in capital	261,108	258,086
Accumulated other comprehensive loss	(61)	(14)
Accumulated deficit	(331,545)	(316,102)
Total stockholders' deficit	(70,471)	(58,004)
Total liabilities and stockholders' deficit	$ 71,099	$ 83,311