Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 157,311	$ 126,870
Short-term investments	13,385	0
Accounts receivable	700	334
Prepaid expenses and other current assets	4,024	1,327
Total current assets	175,420	128,531
Long-term investments	6,554	0
Property and equipment, net	2,245	1,480
Right-of-use assets, net	6,350	6,838
Intangible assets, net	14,928	15,361
Other long-term assets	369	372
Total assets	205,866	152,582
Current liabilities:
Accounts payable	4,638	2,133
Current portion of operating lease liability	2,006	2,052
Liability related to sale of future royalties, current portion	1,822	2,779
Other accrued liabilities	3,176	4,799
Total current liabilities	11,642	11,763
Operating lease liability, net of current portion	4,628	5,156
Liability related to sale of future royalties, net of current portion	13,239	12,150
Other long-term liabilities	122	109
Total liabilities	29,631	29,178
Commitments and contingencies (Note 8)
Stockholders’ equity:
Preferred stock: $0.0001 par value; 5,000,000 shares authorized; none issued and outstanding as of March 31, 2021 and December 31, 2020	0	0
Common stock: $0.0001 par value; 150,000,000 shares authorized; 117,963,912 and 110,271,093 shares issued and outstanding as of March 31, 2021 and December 31, 2020, respectively	12	11
Additional paid-in capital	341,116	272,274
Accumulated deficit	(164,888)	(148,881)
Accumulated other comprehensive loss	(5)	0
Total stockholders’ equity	176,235	123,404
Total liabilities and stockholders’ equity	$ 205,866	$ 152,582