Available-for-Sale Securities Measured at Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	$ 13,511	$ 45,992
Mutual funds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	2,173	2,023
U.S. Government and agency securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		29,737
Asset-backed securities and collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	7,639	8,477
Corporate notes and bonds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		5,755
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	3,699
Level 1
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities
Level 1 | Mutual funds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities
Level 1 | U.S. Government and agency securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities
Level 1 | Asset-backed securities and collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities
Level 1 | Corporate notes and bonds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities
Level 1 | Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities
Level 2
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	7,954	39,649
Level 2 | Mutual funds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	2,173	2,023
Level 2 | U.S. Government and agency securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		29,737
Level 2 | Asset-backed securities and collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	2,082	2,134
Level 2 | Corporate notes and bonds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		5,755
Level 2 | Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	3,699
Level 3
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	5,557	6,343
Level 3 | Asset-backed securities and collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	$ 5,557	$ 6,343