Excess of issue price over par or stated value of the entity's capital stock and amounts received from other transactions involving the entity's stock or stockholders. Includes adjustments to additional paid in capital. Some examples of such adjustments include recording the issuance of debt with a beneficial conversion feature and certain tax consequences of equity instruments awarded to employees. Use this element for the aggregate amount of additional paid-in capital associated with common and preferred stock. For additional paid-in capital associated with only common stock, use the element additional paid in capital, common stock. For additional paid-in capital associated with only preferred stock, use the element additional paid in capital, preferred stock.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 31

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.30(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Subsequent Events (Details) (USD $)	0 Months Ended			12 Months Ended							0 Months Ended
Subsequent Events (Details) (USD $)	Oct. 15, 2013	Oct. 23, 2012	Aug. 01, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013 Actual [Member]	Dec. 31, 2013 Adjustment [Member]	Dec. 31, 2013 Pro Forma [Member]	Feb. 05, 2014 Subsequent Event [Member]
Subsequent Event [Line Items]
Stock issued, underwritten public offering, value	$ 25,900,000	$ 23,000,000	$ 20,400,000	$ 24,094,530	$ 21,476,815	$ 6,722,939					$ 86,000,000
Stock issued underwritten public offering (in shares)	11,500,000	9,200,000	5,600,000								13,200,000
Common stock per share value (in dollars per share)	$ 2.25	$ 2.50	$ 3.57								$ 6.5
Net proceeds from issuance of common stock	24,100,000	21,500,000	18,900,000	24,094,530	21,476,815	18,939,619					80,500,000
Common stock, shares outstanding (in shares)				42,116,964	30,607,916						55,300,000
Current assets:
Cash and cash equivalents				11,483,112	14,344,088	17,988,590	6,324,430	11,483,112	80,534,750	92,017,862
Short-term investments				27,084,980	24,000,000			27,084,980	0	27,084,980
Prepaid and other current assets				2,329,742	1,212,041			2,455,733	0	2,455,733
Total current assets				41,023,825	39,692,448			41,023,825	80,534,750	121,558,575
Non-current assets								476,230	0	476,230
Total assets				41,500,055	40,231,776			41,500,055	80,534,750	122,034,805
LIABILITIES AND STOCKHOLDERS' EQUITY
Total current liabilities				30,838,688	10,065,935			30,838,688	0	30,838,688
Stockholders' equity:
Common stock				42,118	30,608			42,118	13,225	55,343
Additional paid-in capital				289,426,100	261,318,638			289,426,100	80,521,525	369,947,625
Treasury stock				(2,417,247)	(2,279,238)			(2,417,247)	0	(2,417,247)
Accumulated deficit				(276,389,604)	(228,904,167)			(276,389,604)	0	(276,389,604)
Total stockholders' equity				10,661,367	30,165,841	24,254,070	30,567,975	10,661,367	80,534,750	91,196,117
Total liabilities and stockholders' equity				$ 41,500,055	$ 40,231,776			$ 41,500,055	$ 80,534,750	$ 122,034,805