MARKETABLE SECURITIES (Tables)

12 Months Ended

Dec. 31, 2013

Cash And Cash Equivalents [Abstract]

Summary of Available-for-Sale Marketable Securities

The following is a summary of available-for-sale marketable securities at December 31, 2012 and 2013:

	As at December 31, 2013
	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
Available-for-sale - matures within one year:
Corporate bonds	$	2,852	$	6	$	(3	)	$	2,855
Available-for-sale - matures after one year through three years:
Corporate bonds		65,702		134		(227	)		65,609
Total	$	68,554	$	140	$	(230	)	$	68,464

	As at December 31, 2012
	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
Available-for-sale - matures within one year:
Corporate bonds	$	10,964	$	73	$	(4	)	$	11,033
		10,964		73		(4	)		11,033
Available-for-sale - matures after one year through three years:
Certificates of deposits		1,960		—		(1	)		1,959
Foreign government bond		573		2		—			575
Corporate bonds		55,622		391		(237	)		55,776
		58,155		393		(238	)		58,310
Total	$	69,119	$	466	$	(242	)	$	69,343

Summary of Gross Unrealized Losses and Fair Values on Investments

The following table presents gross unrealized losses and fair values for those investments that were in an unrealized loss position as of December 31, 2012 and 2013, and the length of time that those investments have been in a continuous loss position:

	Less than 12 months					12 months or greater
	Fair Value		Gross unrealized loss			Fair Value		Gross unrealized loss
As of December 31, 2013	$	28,535	$	(208	)	$	4,278	$	(22	)
As of December 31, 2012	$	28,711	$	(241	)	$	489	$	(1	)

Summary of Gross Realized Gain and Loss from Sale of Available-for-Sale Marketable Securities

The following table presents gross realized gain and gross realized loss from sale of available-for-sale marketable securities:

	Year ended December 31,
	2011			2012			2013
Gross realized gain from sale of available-for-sale marketable securities	$	77		$	301		$	400
Gross realized loss from sale of available-for-sale marketable securities	$	(23	)	$	(117	)	$	(21	)