Note 19 - Quarterly Financial Data (Unaudited) (Details) - Quarterly Financial Data (Unaudited) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Data (Unaudited) [Abstract]
Product revenue	$ 20,188,488	$ 17,023,346	$ 20,067,407	$ 14,494,489	$ 21,459,124	$ 14,055,440	$ 18,882,277	$ 13,613,328	$ 71,773,730	$ 68,010,169	$ 61,956,386
Total revenue	21,251,328	17,754,438	20,828,377	15,247,011	22,606,465	14,766,611	19,624,769	14,360,660	75,081,154	71,358,505	64,778,635
Cost of product revenue	6,235,334	5,377,568	6,311,332	4,841,170	7,269,886	7,221,028	8,084,226	6,413,481	22,765,404	28,988,621	26,783,738
Gross profit on product revenue	13,953,154	11,645,778	13,756,075	9,653,319	14,189,238	6,834,412	10,798,051	7,199,847
Net income	$ 6,654,369	$ 4,957,258	$ 5,894,892	$ 3,068,002	$ 4,463,223	$ 1,645,250	$ 3,736,868	$ 1,912,119	$ 20,574,521	$ 11,757,460	$ 8,466,680
Per common share information:
Basic net income per share (in Dollars per share)	$ 0.47	$ 0.36	$ 0.44	$ 0.23	$ 0.33	$ 0.12	$ 0.28	$ 0.15	$ 1.46	$ 0.89	$ 0.65
Basic common shares outstanding (in Shares)	14,272,606	13,682,449	13,510,573	13,406,952	13,324,942	13,287,463	13,262,023	13,162,824	14,086,912	13,260,739	13,064,051
Diluted net income per share (in Dollars per share)	$ 0.44	$ 0.33	$ 0.40	$ 0.21	$ 0.31	$ 0.11	$ 0.26	$ 0.14	$ 1.39	$ 0.82	$ 0.62
Diluted common shares outstanding (in Shares)	15,084,738	14,958,965	14,578,927	14,357,110	14,299,211	14,459,154	14,443,794	14,089,946	14,825,599	14,344,577	13,747,813