Condensed Balance Sheets - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents		$ 89,626	$ 78,768	[1]
Short-term investments		34,315	89,321	[1]
Accounts receivable		17	85	[1]
Unbilled license revenue	[1]		5,000
Prepaid expenses and other current assets		3,283	3,197	[1]
Total current assets		127,241	176,371	[1]
Property and equipment, net		4,469	5,611	[1]
Right-of-use assets		4,919
Other assets		1,351	1,350	[1]
Total assets		137,980	183,332	[1]
Current liabilities:
Accounts payable		1,260	1,148	[1]
Accrued compensation and benefits		2,351	2,723	[1]
Uncharged license fees	[1]		1,000
Current portion of operating lease liability		2,318
Accrued and other liabilities		10,404	12,857	[1]
Total current liabilities		16,333	17,728	[1]
Operating lease liability, net of current portion		3,433
Loan payable, long term		49,597	49,209	[1]
Other long-term liabilities	[1]		582
Total liabilities		69,363	67,519	[1]
Commitments and contingencies				[1]
Stockholders' equity:
Preferred stock, $0.0001 par value; 5,000,000 shares authorized; no shares issued and outstanding as of June 30, 2019 and December 31, 2018, respectively				[1]
Common stock, $0.0001 par value; 300,000,000 shares authorized; 62,800,869 and 62,516,627 shares issued and outstanding as of June 30, 2019 and December 31, 2018, respectively		6	6	[1]
Additional paid-in capital		485,718	481,357	[1]
Accumulated deficit		(417,123)	(365,512)	[1]
Accumulated other comprehensive loss		16	(38)	[1]
Total stockholders' equity		68,617	115,813	[1]
Total liabilities and stockholders' equity		$ 137,980	$ 183,332	[1]

[1] Derived from the audited consolidated financial statements included in the Company’s Annual Report on Form 10K for the year ended December 31, 2018.