Summary of Significant Accounting Policies - Product Revenue and Other (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Provision for U.S. product sales allowances and accruals
Gross U.S. product sales	$ 561,255	$ 190,512	$ 120,195
Contractual adjustments	161,665	73,262	48,433
Government rebates	57,774	7,252	70
Total provision for U.S product sales allowances and accruals	219,439	80,514	48,503
U.S. products sales, net	$ 341,816	109,998	71,692
Typical average period from time of product sale to payment of rebate, up to or longer than	3 months
Discounts
Percentage of prompt payment discount to customers	2.00%
Period within which discount is offered to customers for prompt payment	30 days
Accrued percentage of the prompt payment discount	100.00%
Product Returns
Reduction of reserve for product returns		$ 1,800
Reduction of product return reserve impact on earnings per share basic (in dollars per share)		$ 0.08
Reduction of product return reserve impact on earnings per share diluted (in dollars per share)		$ 0.07
Government and Other Rebates
Reduction in Medicaid rebate reserves			$ 600
Reduction in estimated Medicaid rebate reserve, impact per basic and diluted share (in dollars per share)			$ 0.03
Distributor/Wholesaler and Group Purchasing Organization Fees
Period within which fees are billed by the GPO	30 days
Advertising Costs
Advertising costs, including promotional expenses and costs related to trade shows	$ 8,000	$ 2,100	$ 1,900
U.S. Feraheme
Product Returns
Expiration period for products	5 years
Makena
Product Returns
Expiration period for products	3 years