LONG-TERM DEBT (Details) (USD $)	3 Months Ended		1 Months Ended	3 Months Ended			1 Months Ended		3 Months Ended			3 Months Ended				1 Months Ended	3 Months Ended		1 Months Ended				3 Months Ended			1 Months Ended			3 Months Ended		1 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Oct. 31, 2011 Credit Agreement	Jun. 30, 2012 Credit Agreement item	Jun. 30, 2011 Credit Agreement	Mar. 31, 2012 Credit Agreement	Oct. 31, 2011 Credit Agreement Minimum	Oct. 31, 2011 Credit Agreement Maximum	Jun. 30, 2012 Credit Agreement Base rate	Oct. 31, 2011 Credit Agreement Base rate Minimum	Oct. 31, 2011 Credit Agreement Base rate Maximum	Jun. 30, 2012 Credit Agreement LIBOR	Oct. 31, 2011 Credit Agreement LIBOR Minimum	Oct. 31, 2011 Credit Agreement LIBOR Maximum	Oct. 31, 2011 Letter of Credit	Nov. 30, 2011 1.75% Convertible Notes due 2016 ("1.75% Convertible Notes")	Jun. 30, 2012 1.75% Convertible Notes due 2016 ("1.75% Convertible Notes")	Mar. 31, 2012 1.75% Convertible Notes due 2016 ("1.75% Convertible Notes")	Nov. 30, 2011 1.75% Convertible Notes due 2016 ("1.75% Convertible Notes") Conversion Terms at Holder's Option	Nov. 30, 2011 1.75% Convertible Notes due 2016 ("1.75% Convertible Notes") Conversion Terms upon Occurrence of Certain Fundamental Company Changes	Nov. 30, 2011 1.75% Convertible Notes due 2016 ("1.75% Convertible Notes") Conversion Terms, Event of Default	Jun. 30, 2009 4.375% convertible notes due 2014 ("Convertible Notes")	Jun. 30, 2012 4.375% convertible notes due 2014 ("Convertible Notes")	Jun. 30, 2011 4.375% convertible notes due 2014 ("Convertible Notes")	Mar. 31, 2012 4.375% convertible notes due 2014 ("Convertible Notes")	Jun. 30, 2009 4.375% convertible notes due 2014 ("Convertible Notes") 4.375% Convertible Note hedge options	Jun. 30, 2009 4.375% convertible notes due 2014 ("Convertible Notes") 4.375% Convertible Note hedge warrants	Jun. 30, 2009 4.375% convertible notes due 2014 ("Convertible Notes") Conversion Terms at Holder's Option	Jun. 30, 2012 4.375% convertible notes due 2014 ("Convertible Notes") Redemption Terms at Company Option	Jun. 30, 2012 4.375% convertible notes due 2014 ("Convertible Notes") Conversion Terms upon Occurrence of Certain Fundamental Company Changes	Jun. 30, 2009 4.375% convertible notes due 2014 ("Convertible Notes") Conversion Terms, Event of Default
Credit Agreement
Maximum borrowing capacity			$ 100,000,000												$ 25,000,000
Interest rate, variable rate basis									Base Rate			LIBOR
Interest rate added to base rate (as a percent)										1.50%	2.00%		2.50%	3.00%
Interest rate at end of period (as a percent)									4.75%			2.75%
Credit Agreement Availability
Available borrowings				98,336,000		79,069,000
Outstanding letters of credit				1,664,000		1,664,000
Interest expense and fees				159,000	436,000
Increase additional borrowings			40,000,000
Interest coverage ratio for trailing twelve month period, numerator				1
Interest coverage ratio for trailing twelve month period, denominator				1
Maximum liquidity level triggering the requirement to maintain an interest coverage ratio of one to one				30,000,000
Monthly fee on unused available balance (as a percent)							0.375%	0.50%
Convertible Notes
Aggregate principal amount																250,000,000						138,000,000
Interest rate on convertible notes (as a percent)																	1.75%					4.375%	4.375%
Amount pertaining to exercise of over-allotment of debt by underwriters																						18,000,000
Initial conversion rate of common stock per $1 of principal amount of Convertible Notes (in shares)																52.3745						93.6768
Principal amount used for debt instrument conversion ratio																1,000						1,000
Initial conversion price of convertible notes into common stock (in dollars per share)																$ 19.093						$ 10.675	$ 10.675
Number of shares to be converted into common stock																13,094,000						12,927,000
Minimum number of trading days triggering conversion of redemption feature																			20 days									20 days	20 days
The maximum period of consecutive trading days that the entity's common stock closing price to conversion price must exceed a specified percentage of conversion price to trigger conversion of redemption feature of notes																			30 days									30 days	30 days
Target ratio of closing share price to conversion price as a condition for conversion or redemption of Convertible Notes (as a percent)																			130.00%									130.00%	150.00%
Minimum consecutive business days in the measurement period the closing sales price of common stock must exceed a specified percentage of conversion price to trigger conversion feature of note																			5 days									5 days
The maximum period of trading days in the measurement period that the entity's common stock closing price to conversion price must exceed a specified percentage of conversion price to trigger conversion feature of notes																			10 days									10 days
Ratio of closing share price to conversion price as a condition for conversion of Convertible Notes, minimum (as a percent)																			98.00%									98.00%
Redemption price as percentage of principal amount of notes plus accrued and unpaid interest																				100.00%									100.00%	100.00%
Minimum percentage of aggregate principal amount held by bondholders to declare notes due and payable																					25.00%										25.00%
In event of default arising out of certain bankruptcy events, the percentage of principal amount due and payable																					100.00%										100.00%
Adjustment to additional paid-in capital for options to purchase common stock																										43,600,000
Investment warrants exercise price (in dollars per share)																											$ 14.945
Number of shares of common stock that will be settled against warrants																											12,927,000
Total proceeds from warrants credited to additional paid-in capital																											26,300,000
Banking, legal and accounting fees related to issuance of convertible notes																6,875,000						3,410,000
Estimated fair value																197,373,000
Non-convertible borrowing rate (as a percent)																6.90%
Derivative nonmonetary notional amount (in shares)																										12,927,000
Investment options exercise price																										$ 10.675
Carrying amount of the equity component																52,627,000
Banking, legal and accounting fees related to issuance of convertible notes allocated to the liability component																5,428,000
Banking, legal and accounting fees related to issuance of convertible notes allocated to the equity component																1,447,000
Additional information related to convertible notes
Additional paid-in capital																	51,180,000	51,180,000					42,018,000		42,018,000
Principal amount of Convertible Notes																	250,000,000	250,000,000					138,000,000		138,000,000
Unamortized discount of the liability component																	47,021,000	49,291,000					20,096,000		22,369,000
Net carrying amount of Convertible Notes																	202,979,000	200,709,000					117,904,000		115,631,000
Carrying amount of debt issuance costs																	4,684,000	4,979,000					1,308,000		1,479,000
Components of interest expense
Cash interest expense (coupon interest expense)																	1,094,000						1,509,000	1,509,000
Non-cash amortization of discount on Convertible Notes	4,543,000	1,997,000															2,270,000						2,273,000	1,997,000
Amortization of debt issuance costs	511,000	313,000															295,000						171,000	171,000
Total interest expense related to Convertible Notes																	$ 3,659,000						$ 3,953,000	$ 3,677,000