Cost of Revenue (Tables)

12 Months Ended

Dec. 31, 2013

Cost of Revenue

Cost of revenue consists of the following:

	Year ended December 31,
	2011		2012		2013
Personnel expenses	$	678,247	$	795,525	$	904,445
Operational expenses		274,824		313,432		367,213
Depreciation and amortization		51,828		48,809		47,913
	$	1,004,899	$	1,157,766	$	1,319,571