CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 293,408	$ 81,189
Receivable from collaborative partners	5,000	0
Australian tax incentive receivable	173	1,601
Short-term investments	200,406	167,218
Prepaid expenses and other current assets	4,035	2,688
Total current assets	503,022	252,696
Property and equipment, net	1,344	665
Long-term investments	18,616	75,897
Other long-term assets	79	46
Restricted cash	60	60
Total assets	523,121	329,364
Current liabilities:
Accounts payable	6,180	2,323
Accrued expenses	7,145	4,875
Notes payable, current portion	7,500	6,875
Other current liabilities	48	17
Total current liabilities	20,873	14,090
Notes payable, net of current portion	2,409	7,553
Deferred rent	162	140
Stockholders’ equity:
Preferred stock, $0.001 par value, 10,000 shares authorized and no shares, issued or outstanding at September 30, 2018 and December 31, 2017, respectively	0	0
Common stock, $0.001 par value, 500,000 shares authorized, 26,749 shares and 23,791 shares issued and outstanding at September 30, 2018 and December 31, 2017, respectively	27	24
Additional paid in capital	629,887	393,017
Accumulated other comprehensive loss	(541)	(426)
Accumulated deficit	(129,696)	(85,034)
Total stockholders’ equity	499,677	307,581
Total liabilities, preferred stock and stockholders’ equity	$ 523,121	$ 329,364