Note 11 - Summary of Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2016	Jan. 30, 2016	Nov. 01, 2015	Aug. 02, 2015	May 02, 2015	Jan. 31, 2015	Nov. 01, 2014	Aug. 02, 2014	Apr. 30, 2016	May 02, 2015	May 03, 2014
Net sales	$ 179,034	$ 161,687	$ 178,678	$ 185,386	$ 164,592	$ 143,021	$ 163,575	$ 174,637	$ 704,785	$ 645,825	$ 641,135
Gross profit	65,365	52,552	60,621	62,899	55,476	46,090	57,732	59,842	241,437	219,140	217,655
Net income	$ 17,537	$ 11,236	$ 15,312	$ 17,113	$ 12,182	$ 8,808	$ 12,958	$ 15,363	$ 61,198	$ 49,311	$ 43,635
Earnings per common share – basic (in dollars per share)	$ 0.37	$ 0.24	$ 0.33	$ 0.37	$ 0.26	$ 0.19	$ 0.28	$ 0.33	$ 1.31	$ 1.06	$ 0.93
Earnings per common share – diluted (in dollars per share)	$ 0.37	$ 0.24	$ 0.33	$ 0.37	$ 0.26	$ 0.19	$ 0.28	$ 0.33	$ 1.31	$ 1.05	$ 0.92