Fair Value Measurements (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Assets:
Cash and cash equivalents	$ 16,205	$ 22,511
Short-term investments	466	416
Fair value of hedge	483
Total assets	17,154	22,927
Liabilities:
Contingent consideration	22,861	9,921
Total liabilities	22,861	9,921
Level 1 Inputs
Assets:
Cash and cash equivalents	16,205	22,511
Short-term investments	466	416
Fair value of hedge	0
Total assets	16,671	22,927
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Level 2 Inputs
Assets:
Cash and cash equivalents	0	0
Short-term investments	0	0
Fair value of hedge	483
Total assets	483	0
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Level 3 Inputs
Assets:
Cash and cash equivalents	0	0
Short-term investments	0	0
Fair value of hedge	0
Total assets	0	0
Liabilities:
Contingent consideration	22,861	9,921
Total liabilities	$ 22,861	$ 9,921