Investments - Summary of Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	$ 11,779	$ 8,483
Unrealized Losses, Less than 12 Months	40	12
Fair Value, 12 Months or More	284	0
Unrealized Losses, 12 Months or More	2	0
Fair Value	12,063	8,483
Unrealized Losses	42	12
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	8,998	3,994
Unrealized Losses, Less than 12 Months	26	1
Fair Value, 12 Months or More	0	0
Unrealized Losses, 12 Months or More	0	0
Fair Value	8,998	3,994
Unrealized Losses	26	1
Foreign government
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	50	50
Unrealized Losses, Less than 12 Months	0	0
Fair Value, 12 Months or More		0
Unrealized Losses, 12 Months or More		0
Fair Value	50	50
Unrealized Losses	0	0
Corporate debt
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	2,731	4,439
Unrealized Losses, Less than 12 Months	14	11
Fair Value, 12 Months or More	284	0
Unrealized Losses, 12 Months or More	2	0
Fair Value	3,015	4,439
Unrealized Losses	$ 16	$ 11