Cash, Cash Equivalents and Investments - Short and Long-term Investments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Government Agency Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 2,511	$ 11,535
Gross Unrealized Gains	4	20
Gross Unrealized Losses
Estimated Fair Value	2,515	11,555
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	15,833	16,373
Gross Unrealized Gains	13	10
Gross Unrealized Losses	(1)	(7)
Estimated Fair Value	15,845	16,376
Total Short and Long-Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	18,344	27,908
Gross Unrealized Gains	17	30
Gross Unrealized Losses	(1)	(7)
Estimated Fair Value	$ 18,360	$ 27,931