TRADE ACCOUNTS RECEIVABLE, NET OF ALLOWANCE

6 Months Ended

Jun. 30, 2014

TRADE ACCOUNTS RECEIVABLE, NET OF ALLOWANCE

6.    TRADE ACCOUNTS RECEIVABLE, NET OF ALLOWANCE

(in thousands)	June 30,             2014		December 31,             2013
Trade accounts receivable	$	84,167	$	129,007
Unbilled trade accounts receivable		32,340		38,618
Total accounts receivable		116,507		167,625
Allowance for sales credit memos		(1,865)		(1,997)
	$	114,642	$	165,628

Unbilled trade accounts receivable relate to services revenue earned under time and material arrangements, and maintenance and license arrangements that had not been invoiced as of June 30, 2014 and December 31, 2013, respectively.