Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets
Cash and cash equivalents	$ 106,946	$ 85,586
Short-term investments	48,292	54,339
Prepaid expenses and other current assets	1,348	1,122
Total current assets	156,586	141,047
Long-term investments	7,707	18,275
Furniture, fixtures and equipment, net	2,912	240
Other assets, net	8,034	1,523
Total assets	175,239	161,085
Current liabilities
Accounts payable and other current liabilities	17,961	8,336
Interest payable	551	551
Total current liabilities	18,512	8,887
Convertible notes, net of discounts	124,250	124,156
Total liabilities	$ 142,762	$ 133,043
Commitments and contingencies
Stockholders’ equity
Preferred stock, $0.001 par value; 15,000,000 shares authorized as of September 30, 2015 and December 31, 2014; None issued and outstanding	$ 0	$ 0
Common stock, $0.001 par value; 150,000,000 shares authorized as of September 30, 2015 and December 31, 2014; 26,290,705 and 24,018,577 shares issued and outstanding as of September 30, 2015 and December 31, 2014, respectively	26	24
Additional paid-in capital	229,670	171,326
Accumulated other comprehensive loss	(32)	(107)
Accumulated deficit	(197,187)	(143,201)
Total stockholders’ equity	32,477	28,042
Total liabilities and stockholders’ equity	$ 175,239	$ 161,085