XML 19 R30.htm IDEA: XBRL DOCUMENT v3.2.0.727

Convertible debt (Details) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2015 USD ($) $ / shares	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Debt Instrument [Line Items]
Debt Issuance Cost		$ (408)	$ 0
Convertible debt, issuance cost, equity component		$ 1,200
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	2.00%	2.00%
Debt Instrument, Convertible, Conversion Ratio		29.5972
Debt Instrument, Convertible, Stock Price Trigger | $ / shares		$ 33.79
Interest Expense, Debt	$ 2,223	$ 4,408
Debt Instrument, Fair Value Disclosure	110,391	110,391
Debt Instrument, Face Amount	143,800	143,800		$ 143,800
Debt Instrument, Periodic Payment, Interest	719	1,438
Amortization of Debt Discount (Premium)	1,306	2,577
Debt Instrument, Unamortized Discount (Premium), Net	(30,389)	(30,389)		(33,302)
Convertible Debt, Noncurrent	113,361	113,361		110,448
Debt Instrument, Convertible, Carrying Amount of Equity Component	28,714	$ 28,714		28,714
Purchase of convertible bond hedge				(29,411)
Investment Warrants, Exercise Price | $ / shares		$ 45.48
Proceeds from Issuance of Warrants				$ 17,106
Convertible Debt [Member]
Debt Instrument [Line Items]
Debt Issuance Cost		$ 4,300
Amortization of Financing Costs	$ 198	$ 393

X

- Definition

Exercise price of the warrants.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher SEC



-Name Regulation S-X (SX)



-Number 210



-Article 12



-Section 13



-Sentence Column A

+ Details

Name:	invest_InvestmentWarrantsExercisePrice
Namespace Prefix:	invest_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Convertible debt, issuance cost, equity component

+ References

No definition available.

+ Details

Name:	pro_Convertibledebtissuancecostequitycomponent
Namespace Prefix:	pro_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Purchase of convertible bond hedge

+ References

No definition available.

+ Details

Name:	pro_Purchaseofconvertiblebondhedge
Namespace Prefix:	pro_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 230



-SubTopic 10



-Section 45



-Paragraph 28



-Subparagraph (b)



-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585



Reference 2: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 835



-SubTopic 30



-Section 45



-Paragraph 1A



-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399



Reference 3: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 225



-SubTopic 10



-Section S99



-Paragraph 2



-Subparagraph (SX 210.5-03.8)



-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

Name:	us-gaap_AmortizationOfDebtDiscountPremium
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount of noncash expense included in interest expense to issue debt and obtain financing associated with the related debt instruments. Alternate captions include noncash interest expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 230



-SubTopic 10



-Section 45



-Paragraph 28



-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585



Reference 2: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 225



-SubTopic 10



-Section S99



-Paragraph 2



-Subparagraph (SX 210.5-03.8)



-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688



Reference 3: http://www.xbrl.org/2003/role/presentationRef



-Publisher SEC



-Name Regulation S-X (SX)



-Number 210



-Section 04



-Paragraph 8



-Article 9

+ Details

Name:	us-gaap_AmortizationOfFinancingCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 210



-SubTopic 10



-Section S99



-Paragraph 1



-Subparagraph (SX 210.5-02.22)



-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_ConvertibleDebtNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 470



-SubTopic 20



-Section 50



-Paragraph 4



-Subparagraph (a)



-URI http://asc.fasb.org/extlink&oid=6928298&loc=SL6031897-161870

+ Details

Name:	us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 505



-SubTopic 10



-Section 50



-Paragraph 6



-Subparagraph (b)



-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644



Reference 2: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Glossary Conversion Rate



-URI http://asc.fasb.org/extlink&oid=6509012



Reference 3: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 210



-SubTopic 10



-Section S99



-Paragraph 1



-Subparagraph (SX 210.5-02.22(a)(5))



-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682



Reference 4: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 505



-SubTopic 10



-Section 50



-Paragraph 3



-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644



Reference 5: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 505



-SubTopic 10



-Section 50



-Paragraph 7



-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644

+ Details

Name:	us-gaap_DebtInstrumentConvertibleConversionRatio1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

X

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentConvertibleStockPriceTrigger
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 835



-SubTopic 30



-Section 55



-Paragraph 8



-URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400



Reference 2: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 835



-SubTopic 30



-Section 45



-Paragraph 2



-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 825



-SubTopic 10



-Section 50



-Paragraph 10



-Subparagraph (a)



-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13433-108611



Reference 2: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 825



-SubTopic 10



-Section 50



-Paragraph 12



-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13476-108611

+ Details

Name:	us-gaap_DebtInstrumentFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of the required periodic payments applied to interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 210



-SubTopic 10



-Section S99



-Paragraph 1



-Subparagraph (SX 210.5-02.22)



-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPaymentInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 835



-SubTopic 30



-Section 45



-Paragraph 4



-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28567-108399



Reference 2: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 835



-SubTopic 30



-Section 45



-Paragraph 1A



-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399



Reference 3: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 835



-SubTopic 30



-Section 55



-Paragraph 8



-URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400



Reference 4: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 835



-SubTopic 30



-Section 45



-Paragraph 2



-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399



Reference 5: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 835



-SubTopic 30



-Section 45



-Paragraph 3



-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28555-108399

+ Details

Name:	us-gaap_DebtInstrumentUnamortizedDiscountPremiumNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_DebtIssuanceCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount of the cost of borrowed funds accounted for as interest expense for debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 225



-SubTopic 10



-Section S99



-Paragraph 2



-Subparagraph (SX 210.5-03.8)



-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

Name:	us-gaap_InterestExpenseDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 210



-SubTopic 10



-Section S99



-Paragraph 1



-Subparagraph (SX 210.5-02.22(a)(1))



-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebtPercentageBearingFixedInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 230



-SubTopic 10



-Section 45



-Paragraph 14



-Subparagraph (a)



-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3255-108585



Reference 2: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Glossary Financing Activities



-URI http://asc.fasb.org/extlink&oid=6513228

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfWarrants
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_ConvertibleDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: