Commitments and Contingencies (Details) - USD ($)	1 Months Ended
	Jun. 30, 2014	Jun. 30, 2017
Acquisition agreement | OSI Pharmaceuticals | PDGF Licensed Products
Commitments and contingencies
Amount to be paid on achievement of milestone		$ 12,000,000
License Agreements | Archemix | PDGF Licensed Products
Commitments and contingencies
Royalty payable		0
License Agreements | Archemix | Fovista | Achievement of specified clinical and regulatory milestones | Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone		14,000,000
License Agreements | Archemix | Fovista | Achievement of specified commercial milestones | Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone		3,000,000
License Agreements | Archemix | Other anti-PDGF aptamer | Achievement of specified clinical and regulatory milestones | Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone		18,800,000
License Agreements | Archemix | Other anti-PDGF aptamer | Achievement of specified commercial milestones | Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone		3,000,000
License Agreements | Archemix | C5 Licensed Product
Commitments and contingencies
Royalty payable		0
License Agreements | Archemix | C5 Licensed Product | Achievement of specified commercial milestones | Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone		22,500,000
License Agreements | Archemix | C5 Licensed Product | Achievement of specified development, clinical and regulatory milestones | Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone		57,500,000
Supply Agreement | Nektar
Commitments and contingencies
Payment upon entry into Novartis Agreement	$ 19,800,000
Supply Agreement | Nektar | Fovista | Achievement of specified clinical and regulatory milestones | Maximum
Commitments and contingencies
Amount to be paid on achievement of milestone		6,500,000
Supply Agreement | Nektar | Fovista | Achievement of specified commercial milestones
Commitments and contingencies
Amount to be paid on achievement of milestone		$ 3,000,000