SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

9 Months Ended

Sep. 30, 2012

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Schedule of antidilutive shares excluded from computation of diluted net loss per share

	September 30, 2011	September 30, 2012
Stock options	447,025	480,415
Unvested restricted stock and restricted stock units	9,671	40,121
Convertible preferred stock	73,747	73,747
Contingently issuable common stock and common stock warrants associated with Economic Rights	—	435,187
Common stock warrants	834,800	1,973,431
Total shares excluded from calculation	1,365,243	3,002,901