Quarterly Financial Information (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended												12 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009	Sep. 30, 2009	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2010
Quarterly Financial Information (Unaudited)
Net sales	$ 35,690	$ 30,688	$ 27,734	$ 28,878	$ 25,507	$ 25,893	$ 30,039	$ 25,396	$ 33,760	$ 31,266	$ 28,717	$ 31,435	$ 122,990	$ 106,835	$ 125,178
Cost of Goods Sold	23,677	19,797	20,307	20,262	21,752	20,589	21,682	19,492	22,428	20,869	20,640	19,901
Gross profit	12,013	10,891	7,427	8,616	3,755	5,304	8,357	5,904	11,332	10,397	8,077	11,534	38,947	23,320	41,340
Other Operating Expenses	9,407	8,527	6,932	7,171	7,186	6,134	4,536	6,643	7,312	7,745	6,779	6,791
Operating Income (Loss)	2,606	2,364	495	1,445	(3,431)	(830)	3,821	(739)	4,020	2,652	1,298	4,743	6,910	(1,179)	12,713
Other Income (Expense)	(362)	427	654	(1,011)	568	22	(67)	(45)	240	(23)	(62)	(47)	(292)	478	108
Income tax expense (benefit)	812	1,057	519	212	(1,015)	(450)	1,394	(390)	1,288	527	1,170	1,828	2,600	(461)	4,813
Less net income attributable to noncontrolling interest	(17)	(16)	(21)	(16)	(16)	(4)	(7)	(10)	(156)	(9)	(11)	(11)	(70)	(37)	(187)
Net income (loss) attributable to Lannett Company, Inc.	$ 1,415	$ 1,718	$ 609	$ 206	$ (1,864)	$ (362)	$ 2,353	$ (404)	$ 2,816	$ 2,093	$ 55	$ 2,857	$ 3,948	$ (277)	$ 7,821
Earnings (Loss) Per Share - Lannett Company, Inc.
Basic (in dollars per share)	$ 0.05	$ 0.06	$ 0.02	$ 0.01	$ (0.07)	$ (0.01)	$ 0.09	$ (0.02)	$ 0.11	$ 0.08	$ 0.00	$ 0.12	$ 0.14	$ (0.01)	$ 0.32
Diluted (in dollars per share)	$ 0.05	$ 0.06	$ 0.02	$ 0.01	$ (0.07)	$ (0.01)	$ 0.09	$ (0.02)	$ 0.11	$ 0.08	$ 0.00	$ 0.11	$ 0.14	$ (0.01)	$ 0.31