Investments - Amortized Cost and Gross Unrealized Gains and Losses on All Securities (Detail) (Short-term Investments [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 14,216	$ 23,567
Gross Unrealized Gains		806
Gross Unrealized Losses	649	12
Fair Value	13,567	24,361
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,998	6,999
Gross Unrealized Gains
Gross Unrealized Losses		2
Fair Value	2,998	6,997
US Treasury securities and agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		3,509
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value		3,509
FDIC Guaranteed certificates of deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,160	6,453
Gross Unrealized Gains
Gross Unrealized Losses	6	6
Fair Value	6,154	6,447
Common stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,000	2,000
Gross Unrealized Gains		806
Gross Unrealized Losses	642
Fair Value	1,358	2,806
Corporate Notes/Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,058	4,606
Gross Unrealized Gains
Gross Unrealized Losses	1	4
Fair Value	$ 3,057	$ 4,602