CONDENSED STATEMENTS OF CASH FLOWS (Unaudited) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net loss	$ (6,864,109)	$ (10,134,879)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	29,539	26,184
Retirement of fixed assets	0	2,187
Stock compensation and warrant expense	308,008	321,614
Fair value adjustment on warrant liability	2,095,220	3,888,166
Net foreign exchange gain	(132,244)	0
Income from receipt of Mast Therapeutics, Inc. shares	(62,945)	0
Changes in assets and liabilities:
Receivable	99,508	172,325
Interest receivable	(13,651)	29,720
Prepaid expenses and other current assets	(250,057)	211,020
Accounts payable	(1,210,009)	534,804
Accrued expenses and other current liabilities	88,767	916,530
Net cash used in operating activities	(5,911,973)	(4,032,329)
Cash flows from investing activities:
Proceeds from sale of short-term investments	3,000,000	2,989,902
Purchases of equipment and furnishings	(2,444)	(29,467)
Net cash provided by investing activities	2,997,556	2,960,435
Net decrease in cash and cash equivalents	(2,914,417)	(1,071,894)
Cash and cash equivalents at beginning of period	14,344,088	17,988,590
Cash and cash equivalents at end of period	11,429,671	16,916,696
Supplemental disclosure of cash flow information:
Fixed assets purchased on credit	793	0
Cash paid for income taxes	$ 1,600	$ 0