Long-Term Investments - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments Schedule [Abstract]
Auction rate securities held, at par value	$ 2,500,000
Maturity of long-term investment	2038
Assumed interest rate	1.72%
Estimated redemption period	5 years
Fair value input discount rate	1.00%
Recognized cumulative losses	$ 500,000
Unrealized gains (losses) on auction rate securities	48,000	$ (9,000)	$ (200,000)
Cumulative unrealized gains	200,000
Carrying value of auction rate security	2,052,000	$ 1,971,000
Recognized cumulative losses realized	$ 0