Commitments - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Commitments and Contingencies Disclosure [Line Items]
Rent expense	$ 0.5	$ 0.5	$ 1.1	$ 1.0
Minimum
Commitments and Contingencies Disclosure [Line Items]
Term of warranties on certain product sales			12 months
Maximum
Commitments and Contingencies Disclosure [Line Items]
Term of warranties on certain product sales			24 months