Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2011

Accounts Receivable [Abstract]

Accounts Receivable

December 31	2010		2011
Non-U.S. government	$	2,013	$	2,536
U.S. government		1,206		1,039
Commercial		629		877
Total accounts receivable	$	3,848	$	4,452