License and Collaboration Agreements (Tables)

3 Months Ended

Mar. 31, 2013

License and Collaboration Agreements

Schedule of revenue recognized and assets and liabilities under collaborative arrangements

	Three months ended March 31,
(in thousands)	2012		2013
Upfront payment	$	1,250	$	1,250
Milestone payments	1,412		521
Development services	8,142		11,590
Manufacturing services and other	521		741
Total	$	11,325	$	14,102

(in thousands)	December 31, 2012		March 31, 2013
Accounts receivable, billed	$	1,577	$	5,217
Accounts receivable, unbilled	7,690		4,579
Deferred revenue	79,913		77,399