Stockholders' equity

3 Months Ended

Mar. 31, 2013

Stockholders' equity [Abstract]

Stockholders' equity

5.Equity awards

The following is a summary of stock option award activity under the Second Amended and Restated Emergent BioSolutions Inc., 2006 Stock Incentive Plan (the "2006 Plan") and the Emergent BioSolutions Employee Stock Option Plan (the "2004 Plan"):

	2006 Plan					2004 Plan
	Number of Shares			Weighted-Average Exercise Price		Number of Shares		Weighted-Average Exercise Price		Aggregate Intrinsic Value
Outstanding at December 31, 2012		3,550,842		$	17.07		53,156	$	8.86	$	4,801,378
Granted		812,910			14.67		-		-
Exercised		(56,499	)		8.91		-		-
Forfeited		(127,786	)		18.55		-		-
Outstanding at March 31, 2013		4,179,467		$	16.67		53,156	$	8.86	$	2,848,569
Exercisable at March 31, 2013		2,575,695		$	16.86		53,156	$	8.86	$	2,848,569

The following is a summary of restricted stock unit award activity under the 2006 Plan:

	Number of Shares			Weighted-Average Grant Price		Aggregate Intrinsic Value
Outstanding at December 31, 2012		715,609		$	18.41	$	11,478,368
Granted		406,454			14.67
Vested		(291,619	)		14.77
Forfeited		(15,848	)		17.16
Outstanding at March 31, 2013		814,596		$	16.46	$	5,737,280

During the three months ended March 31, 2013, the Company corrected an immaterial prior period error for the three months ended March 31, 2012 of approximately $2.0 million. This immaterial error related to the cash flow presentation of the excess tax benefit attributed to the exercise of non-qualified stock options and restricted stock units. The immaterial error had no impact on the Company's consolidated cash flows, consolidated statements of operations and comprehensive loss or the consolidated balance sheets. The correction of the error is reflected as a reduction of originally reported operating cash flow from operating activities and an increase in originally reported cash flow from financing activities.