M. Restructuring

During 2012 and 2011, we initiated corporate restructurings, including a workforce reduction plan for which we recorded $2.2 million and $3.5 million, respectively, of restructuring related costs, primarily related to employee severance and benefits. The majority of the workforce reduction plan in 2012 was associated with our manufacturing and development infrastructure, including our decision to divest our Cambridge, Massachusetts manufacturing facility. Of the $2.2 million in restructuring expense in 2012, approximately $1.5 million was related to employee severance and benefits, and approximately $0.7 million was related to the write-down of primarily raw material inventory that was no longer usable due to the closure of the facility. The workforce reductions were substantially completed by the end of 2012 and the majority of the related expenses were paid by the end of 2012.

The following table outlines the components of our restructuring expenses which were recorded in operating expenses and current liabilities for the three months ended March 31, 2013 and 2012 (in thousands):

	Three Months Ended March 31, 2013			Three Months Ended March 31, 2012
Accrued restructuring, beginning of period	$	1,383		$	2,366
Employee severance, benefits and related costs	39			85
Payments	(814		)	(609		)
Inventory and other adjustments	—			(79		)
Accrued restructuring, end of period	$	608		$	1,763