Balance Sheets - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 133,930,000	$ 221,861,000
Available for sale securities	155,348,000	74,731,000
Due from Novartis Pharma AG	3,531,000	4,389,000
Prepaid expenses and other current assets	3,078,000	5,504,000
Total current assets	295,887,000	306,485,000
Available for sale securities	0	95,298,000
Property and equipment, net	3,281,000	3,466,000
Deferred tax assets	0	23,113,000
Other assets	462,000	489,000
Total assets	299,630,000	428,851,000
Current liabilities
Accrued research and development expenses	47,240,000	18,820,000
Accounts payable and accrued expenses	12,032,000	12,018,000
Deferred revenue	6,646,000	6,667,000
Total current liabilities	65,918,000	37,505,000
Deferred revenue, long-term	203,330,000	206,399,000
Royalty purchase liability	125,000,000	125,000,000
Total liabilities	394,248,000	368,904,000
Stockholders' equity (deficit)
Preferred stock—$0.001 par value, 5,000,000 shares authorized, no shares issued or outstanding	0	0
Common stock—$0.001 par value, 200,000,000 shares authorized, 35,733,276 and 35,196,567 shares issued and outstanding at December 31, 2016 and December 31, 2015, respectively	36,000	35,000
Additional paid-in capital	504,517,000	465,924,000
Accumulated deficit	(598,959,000)	(405,539,000)
Accumulated other comprehensive loss	(212,000)	(473,000)
Total stockholders' equity (deficit)	(94,618,000)	59,947,000
Total liabilities and stockholders' equity (deficit)	$ 299,630,000	$ 428,851,000