Statements of Convertible Preferred Stock, Stockholders' Equity (Deficit) And Comprehensive Loss (USD $)	Total	Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Deficit	Accumulated Other Comprehensive Income (Loss)	Comprehensive Loss
Convertible preferred stock, Beginning Balance at Dec. 31, 2010		$ 89,799,483
Comprehensive Loss, Beginning Balance at Dec. 31, 2010	0						(20,094,899)
Beginning Balance at Dec. 31, 2010	(96,911,023)		1,203	1,156,681	(98,068,907)	0
Beginning Balance, shares at Dec. 31, 2010			1,203,228
Convertible preferred stock, Beginning Balance, shares at Dec. 31, 2010		11,747,563
Fair value adjustment of the subordinated notes	(644,118)			(644,118)
Net proceeds from initial public offering	78,167,843		14,375	78,153,468
Net proceeds from initial public offering, shares			14,375,000
Conversion of preferred stock to common stock	89,799,482	(89,799,483)	11,747	89,787,735
Conversion of preferred stock to common stock, shares		(11,747,563)	11,747,563
Reclassify warrants to equity	223,031			223,031
Conversion of subordinated notes to common stock	13,983,777		2,336	13,981,441
Conversion of subordinated notes to common stock, shares			2,335,823
Exercise of stock options	41,777		64	41,713
Exercise of stock options, shares			63,223
Stock-based compensation	778,595			778,595
Net loss	(17,707,695)				(17,707,695)		(17,707,695)
Unrealized gain on securities	29,776					29,776	29,776
Convertible preferred stock, Ending Balance at Jun. 30, 2011		0
Comprehensive Loss, Ending Balance at Jun. 30, 2011	29,776						(17,677,919)
Ending Balance at Jun. 30, 2011	$ 67,761,445		$ 29,725	$ 183,478,546	$ (115,776,602)	$ 29,776
Ending Balance, shares at Jun. 30, 2011			29,724,837
Convertible preferred stock, Ending Balance, shares at Jun. 30, 2011		0