Summary of Significant Accounting Policies (Schedule of Revenue by Major Customers) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Genentech [Member] | Avastin [Member]
Entity Wide Revenue Major Customer [Line Items]
Percentage of total revenue (in Percent)	24.00%	31.00%	27.00%	33.00%
Genentech [Member] | Herceptin [Member]
Entity Wide Revenue Major Customer [Line Items]
Percentage of total revenue (in Percent)	24.00%	32.00%	25.00%	32.00%
Genentech [Member] | Lucentis [Member]
Entity Wide Revenue Major Customer [Line Items]
Percentage of total revenue (in Percent)	10.00%	20.00%	11.00%	17.00%
Elan [Member] | Tysabri [Member]
Entity Wide Revenue Major Customer [Line Items]
Percentage of total revenue (in Percent)	8.00%	9.00%	9.00%	11.00%
Depomed [Member] | Glumetza [Member]
Entity Wide Revenue Major Customer [Line Items]
Percentage of total revenue (in Percent)	16.00%	0.00%