CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Statement [Abstract]
Net product sales	$ 29,008	$ 17,372
Operating expenses:
Cost of goods sold	757	274
Research and development	14,672	10,347
Selling, general and administrative	19,125	14,855
Change in valuation of contingent consideration	(2,695)	0
Total operating expenses	37,249	25,476
Operating loss	(8,241)	(8,104)
Other income (expenses), net:
Other income, net	210	311
Interest expense, net	(163)	(3,798)
Finance expense	0	(600)
Change in fair value of derivative instruments	14,340	(36,753)
Bargain purchase gain	0	48,578
Total other income, net	14,387	7,738
Income (Loss) before provision for income taxes	6,146	(366)
Income tax benefit	5,070	40,021
Net income	$ 11,216	$ 39,655
Net earnings per common share, basic (in dollars per share)	$ 0.31	$ 1.46
Net earnings (loss) per common share, diluted (in dollars per share)	$ (0.08)	$ 1.32
Weighted average common shares outstanding, basic (in shares)	36,520,186	27,157,883
Weighted average common shares outstanding, diluted (in shares)	37,947,479	30,380,694
Comprehensive income:
Net income	$ 11,216	$ 39,655
Foreign currency translation	(69)	23
Unrealized loss on marketable securities	(549)	(3,221)
Comprehensive income	$ 10,598	$ 36,457