INVESTMENTS (Details) (USD $)	3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Dec. 31, 2012
Components of Available-for-sale Securities [Line Items]
Amortized Cost	$ 24,623,000		$ 24,623,000	$ 33,589,000
Gains in Accumulated Other Comprehensive Gain			0	5,000
Losses in Accumulated Other Comprehensive Gain			(2,000)	0
Estimated Fair Value	24,621,000		24,621,000	33,594,000
Available-for-sale Securities [Abstract]
Proceeds from sales of available-for-sale-securities	0	0
Net unrealized holding gain (loss) on available-for-sale securities	(2,000)
Tax expense on net unrealized holding gains on available-for-sale securities included in accumulated other comprehensive income	1,000
Available-for-sale securities, debt maturities [Abstract]
Due in one year or less	5,496,000		5,496,000	13,607,000
Due after one year through two years	0		0	3,000,000
Total estimated fair value of available-for-sale debt securities	5,496,000		5,496,000	16,607,000
Ownership percentage in cost method investment	20.00%		20.00%
Money Market Funds [Member]
Components of Available-for-sale Securities [Line Items]
Amortized Cost	19,125,000		19,125,000	16,987,000
Gains in Accumulated Other Comprehensive Gain			0	0
Losses in Accumulated Other Comprehensive Gain			0	0
Estimated Fair Value	19,125,000		19,125,000	16,987,000
Current Non-Government Sponsored Debt Securities [Member]
Components of Available-for-sale Securities [Line Items]
Amortized Cost	5,498,000		5,498,000	13,602,000
Gains in Accumulated Other Comprehensive Gain			0	5,000
Losses in Accumulated Other Comprehensive Gain			(2,000)	0
Estimated Fair Value	5,496,000		5,496,000	13,607,000
Total Current Available-for-sale Securities [Member]
Components of Available-for-sale Securities [Line Items]
Amortized Cost	24,623,000		24,623,000	30,589,000
Gains in Accumulated Other Comprehensive Gain			0	5,000
Losses in Accumulated Other Comprehensive Gain			(2,000)	0
Estimated Fair Value	24,621,000		24,621,000	30,594,000
Non-Current Non-Government Sponsored Debt Securities [Member]
Components of Available-for-sale Securities [Line Items]
Amortized Cost	0		0	3,000,000
Gains in Accumulated Other Comprehensive Gain			0	0
Losses in Accumulated Other Comprehensive Gain			0	0
Estimated Fair Value	0		0	3,000,000
Total Non-Current Available-for-sale Securities [Member]
Components of Available-for-sale Securities [Line Items]
Amortized Cost	0		0	3,000,000
Gains in Accumulated Other Comprehensive Gain			0	0
Losses in Accumulated Other Comprehensive Gain			0	0
Estimated Fair Value	0		0	3,000,000
Investment in Private Company 1 [Member]
Available-for-sale securities, debt maturities [Abstract]
Amount of investments in a private company	4,100,000		4,100,000
Investment in Private Company 2 [Member]
Available-for-sale securities, debt maturities [Abstract]
Amount of investments in a private company	$ 1,000,000		$ 1,000,000