Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Common Share
Net income (loss) attributable to Lannett Company, Inc.	$ (5,490)	$ 36,233	$ 41,211	$ 115,976
Basic weighted average common shares outstanding	36,495,961	35,880,954	36,398,030	35,715,061
Effect of potentially dilutive stock options, warrants and restricted stock awards		1,329,184	985,712	1,367,077
Diluted weighted average common shares outstanding	36,495,961	37,210,138	37,383,742	37,082,138
Earnings (loss) per common share attributable to Lannett Company, Inc.:
Basic (in dollars per share)	$ (0.15)	$ 1.01	$ 1.13	$ 3.25
Diluted (in dollars per share)	$ (0.15)	$ 0.97	$ 1.10	$ 3.13
Anti-dilutive shares excluded in the computation of diluted earnings per share	4,400,000	77,000	2,600,000	490,000