XML 34 R67.htm IDEA: XBRL DOCUMENT v2.4.1.9

Convertible debt (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Interest	$ 162,000us-gaap_DebtInstrumentPeriodicPaymentInterest
Amortization of Financing Costs	46,000us-gaap_AmortizationOfFinancingCosts	50,000us-gaap_AmortizationOfFinancingCosts
Convertible debt, issuance cost, equity component	1,200,000pro_Convertibledebtissuancecostequitycomponent
Debt Instrument, Fair Value Disclosure	114,700,000.000000000us-gaap_DebtInstrumentFairValue
Debt Instrument, Face Amount	143,800,000us-gaap_DebtInstrumentFaceAmount
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	2.00%us-gaap_LongTermDebtPercentageBearingFixedInterestRate
Purchase of convertible bond hedge	29,411,000pro_Purchaseofconvertiblebondhedge	0pro_Purchaseofconvertiblebondhedge	0pro_Purchaseofconvertiblebondhedge
Investment Warrants, Exercise Price	$ 45.48invest_InvestmentWarrantsExercisePrice
Proceeds from Issuance of Warrants	17,106,000us-gaap_ProceedsFromIssuanceOfWarrants	0us-gaap_ProceedsFromIssuanceOfWarrants	0us-gaap_ProceedsFromIssuanceOfWarrants
Debt Instrument, Convertible, Conversion Ratio	29.5972us-gaap_DebtInstrumentConvertibleConversionRatio1
Debt Instrument, Convertible, Stock Price Trigger	$ 33.79us-gaap_DebtInstrumentConvertibleStockPriceTrigger
Debt Issuance Cost	0us-gaap_DebtIssuanceCosts	0us-gaap_DebtIssuanceCosts	(250,000)us-gaap_DebtIssuanceCosts
Debt Instrument, Unamortized Discount (Premium), Net	(33,302,000)us-gaap_DebtInstrumentUnamortizedDiscountPremiumNet
Convertible Debt, Noncurrent	110,448,000us-gaap_ConvertibleDebtNoncurrent	0us-gaap_ConvertibleDebtNoncurrent
Debt Instrument, Convertible, Carrying Amount of Equity Component	28,714,000us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent
Amortization of Debt Discount (Premium)	283,000us-gaap_AmortizationOfDebtDiscountPremium
Convertible Debt [Member]
Debt Instrument [Line Items]
Debt Issuance Cost	$ 4,300,000us-gaap_DebtIssuanceCosts / us-gaap_DebtInstrumentAxis = us-gaap_ConvertibleDebtMember

X

- Definition

Exercise price of the warrants.

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Purchase of convertible bond hedge

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Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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Carrying amount of long-term convertible debt as of the balance sheet date, net of the amount due in the next twelve months or greater than the normal operating cycle, if longer. The debt is convertible into another form of financial instrument, typically the entity's common stock.

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The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

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Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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Price of the entity's common stock which would be required to be attained for the conversion feature embedded in the debt instrument to become effective.

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Face (par) amount of debt instrument at time of issuance.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Amount of the required periodic payments applied to interest.

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The amount of debt discount (net of debt premium) that was originally recognized at the issuance of the instrument that has yet to be amortized.

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Amount of debt issuance costs (for example, but not limited to, legal, accounting, broker, and regulatory fees).

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The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

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The cash inflow from issuance of rights to purchase common shares at predetermined price (usually issued together with corporate debt).

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