Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 211,938	$ 91,060
Short-term investments	41,694	45,502
Prepaid expenses and other current assets	2,910	1,865
Total current assets	256,542	138,427
Long-term investments	1,970	13,808
Furniture, fixtures and equipment, net	4,607	3,816
Other assets, net	2,799	3,076
Total assets	265,918	159,127
Current liabilities
Accounts payable and other current liabilities	13,547	16,565
Interest payable	551	551
Total current liabilities	14,098	17,116
Convertible notes, net of discounts	123,463	123,236
Total liabilities	137,561	140,352
Commitments and contingencies (Note 11)
Stockholders’ equity
Preferred stock, $0.001 par value; 15,000,000 shares authorized as of September 30, 2016 and December 31, 2015; None issued and outstanding	0	0
Common stock, $0.001 par value; 150,000,000 shares authorized as of September 30, 2016 and December 31, 2015; 33,376,170 and 26,458,495 shares issued and outstanding as of September 30, 2016 and December 31, 2015, respectively	33	26
Additional paid-in capital	415,638	236,492
Accumulated other comprehensive loss	(13)	(179)
Accumulated deficit	(287,301)	(217,564)
Total stockholders’ equity	128,357	18,775
Total liabilities and stockholders’ equity	$ 265,918	$ 159,127