Investments in Money Market Funds and Marketable Securities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 26,643,408	$ 34,017,451
Gross Unrealized Gain	6,403	4,637
Gross Unrealized Loss	(9,392)	(9,936)
Fair Value	26,640,419us-gaap_AvailableForSaleSecurities	34,012,152us-gaap_AvailableForSaleSecurities
Marketable securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,089,499	21,792,154
Gross Unrealized Gain	6,403	4,071
Gross Unrealized Loss	(5,693)	(2,675)
Fair Value	23,090,209	21,793,550
Marketable securities \| U.S. Government and agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,716,167	8,165,464
Gross Unrealized Gain	2,174	435
Gross Unrealized Loss	(2,072)	(630)
Fair Value	12,716,269	8,165,269
Marketable securities \| Corporate and other debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,373,332	13,626,690
Gross Unrealized Gain	4,229	3,636
Gross Unrealized Loss	(3,621)	(2,045)
Fair Value	10,373,940	13,628,281
Long-term marketable securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,553,909	12,225,297
Gross Unrealized Gain		566
Gross Unrealized Loss	(3,699)	(7,261)
Fair Value	3,550,210	12,218,602
Long-term marketable securities \| U.S. Government and agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,227,843	11,599,415
Gross Unrealized Gain		466
Gross Unrealized Loss	(207)	(7,034)
Fair Value	1,227,636	11,592,847
Long-term marketable securities \| Corporate and other debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,326,066	625,882
Gross Unrealized Gain		100
Gross Unrealized Loss	(3,492)	(227)
Fair Value	$ 2,322,574	$ 625,755

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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