Restructuring Charges - Roll-forward of the accrued restructuring expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
	Mar. 31, 2013	Jun. 30, 2013
Restructuring Reserve Disclosures [Line Items]
Restructuring charge	$ 539	$ 539
Severance [Member]
Restructuring Reserve Disclosures [Line Items]
Accrued at January 1, 2013
Restructuring charge	437	437
Payments		(379)
Accrued at June 30, 2013		$ 58