Interim Financial Results (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Summary of selected quarterly financial information
Revenue, net	$ 56,170	$ 56,012	$ 58,167	$ 55,609	$ 54,033	$ 50,562	$ 49,482	$ 49,127	$ 225,958	$ 203,204	$ 199,489
Gross profit	46,460	46,742	48,373	46,410	45,962	41,641	40,365	40,388	187,985	168,356	166,033
Net income	$ 3,907	$ 1,782	$ 829	$ 911	$ 2,992	$ 1,635	$ 317	$ 817	$ 7,429	$ 5,761	$ 1,608
Per common share:
Income per share, basic (dollars per share)	$ 0.27	$ 0.13	$ 0.06	$ 0.07	$ 0.20	$ 0.12	$ 0.02	$ 0.06	$ 0.53	$ 0.41	$ 0.12
Income per share, diluted (dollars per share)	$ 0.26	$ 0.12	$ 0.06	$ 0.06	$ 0.21	$ 0.12	$ 0.02	$ 0.06	$ 0.50	$ 0.41	$ 0.11