Concentration of Business Risk

3 Months Ended

Mar. 31, 2013

Concentration of Business Risk

Concentration of Business Risk

5. Concentration of Business Risk

We have historically funded our operations from collaborations with corporate partners and a relatively small number of partners have accounted for a significant percentage of our revenue. Revenue from significant partners, which is defined as ten percent or more of our total revenue, was as follows:

	Three Months Ended March 31,
	2013		2012
Partner A	58	%	71	%
Partner B	23	%	9	%

Contract receivables from four significant partners comprised approximately 88 percent of our contract receivables at March 31, 2013. Contract receivables from four significant partners comprised approximately 83 percent of our contract receivables at December 31, 2012.