Accounts Receivable

6 Months Ended

Jun. 30, 2013

Accounts Receivable [Abstract]

Accounts Receivable

6. Accounts Receivable

Our accounts receivable represent amounts due the Company from collaborators, royalty payments, research grants and the sales of research reagents. These amounts are considered to be short-term as they are expected to be collected within one year and we believe carrying value approximates fair value. Accounts receivable as of the dates indicated below consisted of the following:

	June 30, 2013		December 31, 2012
Collaborators	$	60	$	6,125
Royalties		1,185		781
Research grants		-		12
Other		5		19
Total	$	1,250	$	6,937

The decrease in accounts receivable as of June 30, 2013, is primarily due to collection in the first quarter of the $5.0 million upfront payment related to the out-licensed C. difficile program.