Short-Term Investments - Available-for-Sale Securities Recorded at Fair Value with Unrealized Gains or Losses (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized cost basis	$ 2,202	$ 3,079
Gross unrealized gain (loss)	(1)	(1)
Fair value	2,201	3,078
Corporate notes, bonds and paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost basis	1,002	919
Gross unrealized gain (loss)		(1)
Fair value	1,002	918
Government securities/money market [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost basis	1,200	2,160
Gross unrealized gain (loss)	(1)
Fair value	$ 1,199	$ 2,160