Cash, Cash Equivalents, and Investments (Tables)

12 Months Ended

Dec. 31, 2012

Cash, Cash Equivalents and Investments [Abstract]

Summary of cash, cash equivalents and held-to-maturity investments by type

	December 31, 2012									December 31, 2011
			Gross		Gross							Gross		Gross
			Unrealized		Unrealized			Fair				Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value		Cost		Gains		Losses			Value
Cash and money market funds	$	36,126,791	$	—	$	—		$	36,126,791	$	21,300,733	$	—	$	—		$	21,300,733
Corporate bonds		958		—		—			958		5,008,189		—		(3,238	)		5,004,951
Certificate of deposit		1,680,000		—		(1,488	)		1,678,512		100,000		—		(69	)		99,931
Total cash, cash equivalents and investments	$	37,807,749	$	—	$	(1,488	)	$	37,806,261	$	26,408,922	$	—	$	(3,307	)	$	26,405,615

Summarized classification of short term and Long term investments

	2012		2011
Cash	$	19,811,735	$	6,061,523
Cash equivalents		16,315,056		15,239,210
Total cash and cash equivalents		36,126,791		21,300,733
Short-term investments		1,680,958		5,108,189
Total cash, cash equivalents and investments	$	37,807,749	$	26,408,922