Legal Matters (Details) (Pending litigation, USD $)				0 Months Ended		1 Months Ended		12 Months Ended	0 Months Ended
	Dec. 31, 2012 patent_litigation	Dec. 31, 2012 United States patent_litigation	Dec. 31, 2012 Europe patent_litigation	Sep. 25, 2012 First Davis-Smyth Case claim	Sep. 21, 2012 First Davis-Smyth Case claim	Nov. 30, 2010 First Davis-Smyth Case claim	Jan. 17, 2012 First Davis-Smyth Case claim	Dec. 31, 2012 License agreement with Genentech United States	Sep. 25, 2012 Second Davis-Smyth Case patent_litigation	Sep. 21, 2012 Second Davis-Smyth Case patent_litigation	Dec. 23, 2011 Second Davis-Smyth Case claim
Loss Contingencies [Line Items]
Number of patent litigations	5	2	3
Number of new claims filed				1	2	4			1	2	4
Amount of payment to be made upon reaching minimum sales target								$ 60,000,000
Cumulative sales range, minimum								400,000,000
Royalty payment percentage of cumulative sales within cumulative sales range								4.75%
Cumulative sales range, maximum								$ 3,000,000,000
Royalty payment percentage of cumulative sales over range								5.50%
Number of pending claims							4