(4) Fair Value Measurements (Details) (USD $)	Sep. 30, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash equivalents:
Money market funds	$ 3,824,865	$ 8,129,960
Total cash equivalents	3,824,865	8,129,960
Marketable securities:
Corporate debt and government securities	13,201,701	20,894,328
Auction rate securities	489,999	611,082
Total marketable securities	13,691,700	21,505,410	21,505,410
Total assets measured at fair value	17,516,565	29,635,370
Level 1 Member
Cash equivalents:
Money market funds	3,824,865	8,129,960
Total cash equivalents	3,824,865	8,129,960
Marketable securities:
Corporate debt and government securities	0	0
Auction rate securities	0	0
Total marketable securities	0	0
Total assets measured at fair value	3,824,865	8,129,960
Level 2 Member
Cash equivalents:
Money market funds	0	0
Total cash equivalents	0	0
Marketable securities:
Corporate debt and government securities	13,201,701	20,894,328
Auction rate securities	0	0
Total marketable securities	13,201,701	20,894,328
Total assets measured at fair value	13,201,701	20,894,328
Level 3 Member
Cash equivalents:
Money market funds	0	0
Total cash equivalents	0	0
Marketable securities:
Corporate debt and government securities	0	0
Auction rate securities	489,999	611,082
Total marketable securities	489,999	611,082
Total assets measured at fair value	$ 489,999	$ 611,082