Summary of Significant Accounting Policies (Details 3) (USD $)	3 Months Ended		9 Months Ended	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restricted Cash
Total restricted cash				$ 3,300,000	$ 500,000
Escrow payment related to business development transaction				2,883,000
Restricted cash related to security deposits				400,000	460,000
Advertising Costs
Advertising costs, including promotional expenses and costs related to trade shows				1,900,000	1,800,000	3,100,000
Provision for U.S. product sales allowances and accruals
Discounts and chargebacks				37,098,000	26,517,000	13,851,000
Government and other rebates				10,868,000	6,058,000	8,544,000
Medicaid rebate reserve adjustment	600,000	600,000	2,200,000	(568,000)	(621,000)	(2,532,000)
Returns				952,000	(1,516,000)	1,259,000
Total provision for U.S. product sales allowances and accruals				48,350,000	30,438,000	21,122,000
Total gross U.S. product sales				119,712,000	88,725,000	73,219,000
Total provision for U.S. product sales allowances and accruals as a percent of total gross U.S. product sales				40.00%	34.00%	29.00%
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%
Government and Other Rebates
Reduction in Medicaid rebate reserves				600,000	600,000	2,500,000
Reduction in estimated Medicaid rebate reserve, impact per basic and diluted share (in dollars per share)				$ 0.03	$ 0.03	$ 0.12
Distributor/Wholesaler and Group Purchasing Organization Fees
Period within which fees are billed by the GPO				30 days
Product Returns
Current expiration period for packaged products				5 years
Reduction of reserve for product returns					2,200,000
Expiration period for certain manufactured Feraheme lots					2 years
Product returns provision applied to gross sales					1,500,000
Reduction in estimated product returns reserve, impact per basic and diluted share (in dollars per share)					$ 0.10
Shipping and Handling Costs
Costs for shipping and handling services				$ 300,000	$ 200,000	$ 100,000
Laboratory and production equipment
Property and Equipment
Estimated useful lives				5 years
Furniture and fixtures
Property and Equipment
Estimated useful lives				5 years