Marketable Securities and Fair Value Disclosures - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale Securities, estimated fair value	$ 6,309,000		$ 6,309,000		$ 5,870,000
Additional other-than-temporary impairment losses on marketable securities	0	0	0	0
Transfers of assets or liabilities between Level 1 and Level 2 of the fair value measurement hierarchy	0		0
Transfers of assets or liabilities between Level 1 and Level 3 of the fair value measurement hierarchy	0		0
Impairment of intangible asset	0	0	0	1,494,000
Nitro Customer List [Member]
Schedule of Available-for-sale Securities [Line Items]
Impairment of intangible asset			$ 0	$ 1,500,000