CONDENSED BALANCE SHEETS - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 22,154,000	$ 26,586,000
Short-term investments	29,856,000	33,574,000
Prepaid expenses and other current assets	3,455,000	3,082,000
Total current assets	55,465,000	63,242,000
Long-term investments	1,408,000	26,997,000
Property and equipment, net	1,579,000	1,692,000
Restricted cash and other assets	26,000	345,000
Total assets	58,478,000	92,276,000
Current liabilities:
Accounts payable	344,000	1,169,000
Accrued expenses	6,118,000	4,274,000
Current portion of note payable	284,000	261,000
Current portion of deferred revenue	1,111,000	1,111,000
Total current liabilities	7,857,000	6,815,000
Deferred revenue, net of current portion	429,000	1,262,000
Note payable, net of current portion	285,000	501,000
Other liabilities	35,000	116,000
Total liabilities	8,606,000	8,694,000
Commitments and contingencies
Stockholders' equity:
Common stock, $0.001 par value, Authorized - 280,000 shares; Issued and outstanding - 121,411 and 121,265 shares at September 30, 2016 and December 31, 2015, respectively	121,000	121,000
Additional paid-in capital	589,044,000	583,676,000
Accumulated deficit	(539,292,000)	(500,081,000)
Accumulated other comprehensive income (loss)	(1,000)	(134,000)
Total stockholders' equity	49,872,000	83,582,000
Total liabilities and stockholders' equity	58,478,000	92,276,000
Series A convertible preferred stock
Stockholders' equity:
Convertible preferred stock