Investments - Summary of Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	$ 1,261	$ 11,779
Unrealized Losses, Less than 12 Months	2	40
Fair Value, 12 Months or More	411	284
Unrealized Losses, 12 Months or More	1	2
Fair Value	1,672	12,063
Unrealized Losses	3	42
U.S. Treasury securities, obligations of U.S. Government agencies and Municipals
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	243	8,998
Unrealized Losses, Less than 12 Months	0	26
Fair Value, 12 Months or More	0	0
Unrealized Losses, 12 Months or More	0	0
Fair Value	243	8,998
Unrealized Losses	0	26
Foreign government
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months		50
Unrealized Losses, Less than 12 Months		0
Fair Value, 12 Months or More
Unrealized Losses, 12 Months or More
Fair Value		50
Unrealized Losses		0
Corporate debt
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	1,018	2,731
Unrealized Losses, Less than 12 Months	2	14
Fair Value, 12 Months or More	411	284
Unrealized Losses, 12 Months or More	1	2
Fair Value	1,429	3,015
Unrealized Losses	$ 3	$ 16