Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 78,768	$ 75,383
Short-term investments	89,321	58,593
Accounts receivable	85	10,796
Unbilled license revenue	5,000
Prepaid expenses and other current assets	3,197	4,940
Total current assets	176,371	149,712
Property and equipment, net	5,611	8,032
Other assets	1,350	159
Total assets	183,332	157,903
Current liabilities:
Accounts payable	1,148	3,933
Accrued compensation and benefits	2,723	3,229
Uncharged license fees	1,000
Accrued and other liabilities	12,857	10,709
Total current liabilities	17,728	17,871
Loan payable, long term	49,209
Other long-term liabilities	582	720
Total liabilities	67,519	18,591
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.0001 par value; 5,000,000 shares authorized; no shares issued and outstanding as of December 31, 2018 and December 31, 2017, respectively.
Common stock, $0.0001 par value; 300,000,000 shares authorized; 62,516,627 and 47,534,979 shares issued and outstanding as of December 31, 2018 and December 31, 2017, respectively.	6	5
Additional paid-in capital	481,357	417,568
Accumulated deficit	(365,512)	(278,214)
Accumulated other comprehensive loss	(38)	(47)
Total stockholders' equity	115,813	139,312
Total liabilities and stockholders' equity	$ 183,332	$ 157,903