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STOCK-BASED COMPENSATION (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2015
period
Mar. 31, 2014
Nov. 09, 2010
Stock-based compensation, additional disclosure      
Closing stock price (in dollars per share) $ 1.43us-gaap_SharePrice    
Stock-based compensation plans      
Stock-based compensation expense $ 153us-gaap_AllocatedShareBasedCompensationExpense $ 613us-gaap_AllocatedShareBasedCompensationExpense  
ESPP      
Stock-based compensation plans      
Shares reserved for issuance under stock purchase plan     166,667us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
/ us-gaap_PlanNameAxis
= us-gaap_EmployeeStockMember
Discount rate (as a percent) 10.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate
/ us-gaap_PlanNameAxis
= us-gaap_EmployeeStockMember
   
Number of Offering periods 4stri_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNumberOfOfferingPeriods
/ us-gaap_PlanNameAxis
= us-gaap_EmployeeStockMember
   
Stock-based compensation expense 0us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_PlanNameAxis
= us-gaap_EmployeeStockMember
0us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_PlanNameAxis
= us-gaap_EmployeeStockMember
 
Number of shares available for grant or purchase 159,175us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
/ us-gaap_PlanNameAxis
= us-gaap_EmployeeStockMember
   
2009 Equity Incentive Plan      
Stock-based compensation      
Number of shares reserved for issuance 4,133,133us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
/ us-gaap_PlanNameAxis
= stri_EquityIncentivePlan2009Member
   
Percentage of award vesting 33.00%us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
/ us-gaap_PlanNameAxis
= stri_EquityIncentivePlan2009Member
   
Stock-based compensation plans      
Number of shares available for grant or purchase 1,542,652us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
/ us-gaap_PlanNameAxis
= stri_EquityIncentivePlan2009Member
   
Employee stock option      
Stock-based compensation      
Expiration period 10 years    
Assumptions used to estimate the fair values of the stock options granted      
Risk-free interest rate (as a percent) 1.80%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Expected volatility (as a percent) 68.40%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Expected life (in years) 6 years 10 months 24 days    
Forfeiture rate 5.00%stri_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Weighted-average estimated fair value of options granted during the period (in dollars per share) $ 0.99us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Number of Shares      
Options granted (in shares) 1,964,665us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Outstanding at the end of the period (in shares) 1,964,665us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Vested and exercisable at the end of the period (in shares) 1,964,665us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Vested and exercisable at the end of the period and expected to vest thereafter (in shares) 1,788,135us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Weighted-Average Exercise Price      
Options granted (in dollars per share) $ 1.52us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Outstanding at the end of the period (in dollars per share) $ 1.52us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Vested and exercisable at the end of the period (in dollars per share) $ 1.52us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Vested and exercisable at the end of the period and expected to vest thereafter (in dollars per share) $ 1.52us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Weighted-Average Remaining Contractual Term (in years)      
Outstanding at the end of the period 9 years 10 months 10 days    
Vested and exercisable at the end of the period 9 years 10 months 10 days    
Vested and exercisable at the end of the period and expected to vest thereafter 9 years 10 months 10 days    
Weighted-Average Grant-Date Fair Value      
Options granted (in dollars per share) $ 0.99us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Outstanding at the end of the period (in dollars per share) $ 0.99stri_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Vested and exercisable at the end of the period (in dollars per share) $ 0.99stri_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Vested and exercisable at the end of the period and expected to vest thereafter (in dollars per share) $ 0.99stri_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Aggregate Intrinsic Value      
Options granted (177)stri_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodClosingStockPriceIntrinsicValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Outstanding at the end of the period (177)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Vested and exercisable at the end of the period (177)us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Vested and exercisable at the end of the period and expected to vest thereafter (161)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Unrecognized compensation cost      
Unrecognized compensation cost 1,837us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Weighted-average remaining vesting period of recognition 1 year 8 months 12 days    
Stock-based compensation plans      
Term of U.S. Treasury zero-coupon strip 10 years    
Expected amount of dividend to be distributed 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendPayments
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Employee stock option | Minimum      
Stock-based compensation      
Vesting period 3 years    
Employee stock option | Maximum      
Stock-based compensation      
Vesting period 4 years    
Restricted common stock      
Unrecognized compensation cost      
Unrecognized compensation cost $ 9us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
   
Number of units      
Unvested at the beginning of the period (in shares) 7,379us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
   
Granted (in shares) 7,561us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
   
Vested (in shares) (7,561)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
   
Unvested at the end of the period (in shares) 7,379us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
   
Expected to vest at the end of the period (in shares) 7,379stri_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedAndExpectedToVestNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
   
Restricted common stock | Maximum      
Unrecognized compensation cost      
Weighted-average remaining vesting period of recognition 1 month 6 days