Earnings (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Earnings (Loss) Per Common Share
Net income (loss) attributable to Lannett Company, Inc.	$ 14,929	$ (5,490)	$ (6,307)	$ 41,211
Basic weighted average common shares outstanding	36,849,208	36,495,961	36,785,829	36,398,030
Effect of potentially dilutive stock options, warrants and restricted stock awards	903,096			985,712
Diluted weighted average common shares outstanding	37,752,304	36,495,961	36,785,829	37,383,742
Earnings (loss) per common share attributable to Lannett Company, Inc.:
Basic (in dollars per share)	$ 0.41	$ (0.15)	$ (0.17)	$ 1.13
Diluted (in dollars per share)	$ 0.40	$ (0.15)	$ (0.17)	$ 1.10
Anti-dilutive shares excluded in the computation of diluted earnings per share	3,000,000	4,400,000	4,400,000	2,600,000