Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 194,078	$ 197,945
Short-term investments	87,256	35,717
Prepaid expenses and other current assets	2,065	4,028
Total current assets	283,399	237,690
Long-term investments	901	0
Property, plant and equipment, net	19,246	7,857
Other assets	2,656	2,707
Total assets	306,202	248,254
Current liabilities
Accounts payable and other current liabilities	18,045	18,820
Interest payable	551	551
Total current liabilities	18,596	19,371
Convertible notes, net	123,769	123,539
Other non-current liabilities	4,569	0
Total liabilities	146,934	142,910
Commitments and contingencies (Note 11)
Stockholders’ equity
Preferred stock, $0.001 par value; 15,000,000 shares authorized as of September 30, 2017 and December 31, 2016; None issued and outstanding	0	0
Common stock, $0.001 par value; 150,000,000 shares authorized as of September 30, 2017 and December 31, 2016; 36,426,830 and 33,458,607 shares issued and outstanding as of September 30, 2017 and December 31, 2016, respectively	36	33
Additional paid-in capital	562,545	422,002
Accumulated other comprehensive loss	(98)	(68)
Accumulated deficit	(403,215)	(316,623)
Total stockholders’ equity	159,268	105,344
Total liabilities and stockholders’ equity	$ 306,202	$ 248,254