Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Retained Earnings	Other Comprehensive Loss
BEGINNING BALANCE at Dec. 31, 2014	$ 356,307	$ 342,252	$ 29,250	$ (15,195)
BEGINNING BALANCE (in Shares) at Dec. 31, 2014		111,735,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net (loss) income	150,798		150,798
Exercise of stock options (in Shares)		2,514,000
Exercise of stock options	10,503	$ 10,503
Employee stock purchase plan issuances (In Shares)		66,000
Employee stock purchase plan issuances	1,413	$ 1,413
Restricted stock units (in Shares)		16,000
Restricted stock units	3,814	$ 3,814
Stock-based compensation expense	9,183	9,183
Foreign currency translation loss	(2,051)			(2,051)
Excess tax benefit – stock compensation	47,997	$ 47,997
Unrealized holding loss on available-for-sale securities	104			104
Convertible note conversions (in Shares)		5,096,000
Convertible note conversions	43,497	$ 43,497
Akorn AG pension liability adjustment	0
Exercise of warrants	0
ENDING BALANCE at Dec. 31, 2015	621,565	$ 458,659	180,048	(17,142)
ENDING BALANCE (in Shares) at Dec. 31, 2015		119,427,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net (loss) income	$ 184,243		184,243
Common stock repurchases (in Shares)	(1,800,000)	(1,808,000)
Common stock repurchases	$ (45,000)		(45,000)
Exercise of stock options (in Shares)		1,792,000
Exercise of stock options	13,953	$ 13,953
Restricted stock units (in Shares)		184,000
Restricted stock units	4,091	$ 4,091
Stock-based compensation expense	11,321	$ 11,321
Foreign currency translation loss	(1,941)			(1,941)
Excess tax benefit – stock compensation (in Shares)		(138,000)
Excess tax benefit – stock compensation	(4,158)	$ (4,158)
Unrealized holding loss on available-for-sale securities	740			740
Convertible note conversions (in Shares)		4,933,000
Convertible note conversions	43,215	$ 43,215
Akorn AG pension liability adjustment	(3,624)			(3,624)
Other	(5,221)	(5,221)
ENDING BALANCE at Dec. 31, 2016	$ 819,184	$ 521,860	319,291	(21,967)
ENDING BALANCE (in Shares) at Dec. 31, 2016	124,390,217	124,390,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net (loss) income	$ (24,550)		(24,550)
Exercise of stock options (in Shares)		625,000
Exercise of stock options	9,673	$ 9,673
Restricted stock units (in Shares)		138,000
Restricted stock units	7,736	$ 7,736
Stock-based compensation expense	13,282	$ 13,282
Foreign currency translation loss	6,150			6,150
Stock compensation plan withholdings for employee taxes (in Shares)		(62,000)
Stock compensation plan withholdings for employee taxes	(2,079)	$ (2,079)
Unrealized holding loss on available-for-sale securities	267			267
Akorn AG pension liability adjustment	1,582			1,582
Other	0
ENDING BALANCE at Dec. 31, 2017	$ 831,245	$ 550,472	$ 294,741	$ (13,968)
ENDING BALANCE (in Shares) at Dec. 31, 2017	125,090,522	125,091,000