Commitments and Contingencies (Details) (USD $) Share data in Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Commitments [Abstract]
Number of Leases	2
Long-term Purchase Commitment [Line Items]
Future minimum rental payments under leases	$ 1,400,000
General and administrative expense	12,657,000	11,523,000	10,311,000
Rent expense charged to operations	1,000,000	1,000,000	500,000
Future minimum rental payments under operating leases [Abstract]
2013	1,188,000
2014	1,201,000
2015	498,000
2016	425,000
Total	3,312,000
Cacchillo v. Insmed [Abstract]
Number of claims dismissed	6
Pilkiewicz v. Transave LLC [Abstract]
Number of shares under appraisal of combined common stock holdings of Transave (in shares)	7.77
Total holdback shares as securities for indemnification payments due under merger agreement (in shares)	1,760,000
Richmond facility [Member]
Long-term Purchase Commitment [Line Items]
Total future minimum lease payments	1,900,000
General and administrative expense		1,200,000
Remaining rental accrual	$ 900,000