Investments - Amortized Cost and Gross Unrealized Gains and Losses on All Securities (Detail) (Short-term Investments [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 36,391	$ 14,216
Gross Unrealized Gains	1
Gross Unrealized Losses	911	649
Fair Value	35,481	13,567
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,995	2,998
Gross Unrealized Gains	1
Gross Unrealized Losses
Fair Value	5,996	2,998
FDIC Guaranteed certificates of deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,240	6,160
Gross Unrealized Gains
Gross Unrealized Losses	2	6
Fair Value	4,238	6,154
Common stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,000	2,000
Gross Unrealized Gains
Gross Unrealized Losses	891	642
Fair Value	1,109	1,358
Corporate notes/bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	24,156	3,058
Gross Unrealized Gains
Gross Unrealized Losses	18	1
Fair Value	$ 24,138	$ 3,057