Note 20 - Quarterly Financial Data (Unaudited) (Details) - Quarterly Financial Data (Unaudited) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Data (Unaudited) [Abstract]
Product revenue	$ 17,880,125	$ 21,975,312	$ 21,267,156	$ 14,351,405	$ 20,188,488	$ 17,023,346	$ 20,067,407	$ 14,494,489	$ 75,473,998	$ 71,773,730	$ 68,010,169
Total revenue	23,254,469	22,055,423	26,274,660	34,010,287	21,251,328	17,754,438	20,828,377	15,247,011	105,594,839	75,081,154	71,358,505
Cost of product revenue	5,511,586	5,724,800	5,332,913	4,361,019	6,235,334	5,377,568	6,311,332	4,841,170	20,930,318	22,765,404	28,988,621
Gross profit on product revenue	12,368,539	16,250,512	15,934,243	9,990,386	13,953,154	11,645,778	13,756,075	9,653,319
Net income	$ 7,816,076	$ 6,170,800	$ 9,302,350	$ 15,030,253	$ 6,654,369	$ 4,957,258	$ 5,894,892	$ 3,068,002	$ 38,319,479	$ 20,574,521	$ 11,757,460
Per common share information:
Basic net income per share (in Dollars per share)	$ 0.53	$ 0.42	$ 0.63	$ 1.04	$ 0.47	$ 0.36	$ 0.44	$ 0.23	$ 2.61	$ 1.46	$ 0.89
Basic common shares outstanding (in Shares)	14,800,813	14,758,781	14,687,747	14,461,367	14,272,606	13,682,449	13,510,573	13,406,952
Diluted net income per share (in Dollars per share)	$ 0.51	$ 0.40	$ 0.60	$ 0.97	$ 0.44	$ 0.33	$ 0.40	$ 0.21	$ 2.51	$ 1.39	$ 0.82
Diluted common shares outstanding (in Shares)	15,277,583	15,434,875	15,492,732	15,499,447	15,084,738	14,958,965	14,578,927	14,357,110	15,269,435	14,825,599	14,344,577