Net Loss Per Share Attributable to Common Stockholders (Tables)

3 Months Ended

Mar. 31, 2014

Net Loss Per Share Attributable to Common Stockholders

Schedule of anti-dilutive securities excluded from the calculation of weighted average common shares outstanding

	Three months ended March 31,
	2014	2013
Unvested restricted common stock	63,668	353,379
Stock options	8,121,589	5,876,486
RSUs	1,935,026	382,004