Cash and Cash Equivalents, Marketable Securities and Restricted Cash (Tables)

3 Months Ended

Mar. 31, 2013

Schedule Of Cash Cash Equivalents Marketable Securities And Restricted Cash [Table Text Block]

	March 31, 2013		December 31, 2012
Cash and cash equivalents	$	29,817,517	$	23,845,360
Current and noncurrent marketable securities		29,194,956		35,394,318
Restricted cash		1,301,000		1,301,000
Total cash and cash equivalents, current and noncurrent marketable securities and restricted cash	$	60,313,473	$	60,540,678