Amount of investment in debt and equity securities categorized neither as trading securities nor held-to-maturity securities and intended be sold or mature one year or operating cycle, if longer.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562

+ Details

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

- Definition

Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bb)

-URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueAssetsLevel1ToLevel2TransfersAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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

- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bbb)

-URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueInputsDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByLiabilityClassAxis=us-gaap_WarrantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Summary of Significant Accounting Policies (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value of Financial Instruments
Total assets measured at fair value	$ 29,790	$ 22,511
Transfers between Level 1 and Level 2	0	0
Total liabilities measured at fair value	89
Warrant [Member]
Fair Value of Financial Instruments
Total liabilities measured at fair value	89		157
Fair Value, Inputs, Level 3 [Member]
Fair Value of Financial Instruments
Total liabilities measured at fair value	89
Fair Value, Inputs, Level 3 [Member] \| Financing derivative
Fair Value of Financial Instruments
Total liabilities measured at fair value	89
Fair Value Inputs, Discount Rate	14.00%
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair Value of Financial Instruments
Total assets measured at fair value	9,663	53,511
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Money Market Funds [Member]
Fair Value of Financial Instruments
Total assets measured at fair value	9,663	53,511
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value of Financial Instruments
Total assets measured at fair value	29,790	22,511
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| US Government Corporations and Agencies Securities [Member]
Fair Value of Financial Instruments
Total assets measured at fair value	13,770	12,301
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Commercial Paper [Member]
Fair Value of Financial Instruments
Total assets measured at fair value	1,500	8,249
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Corporate Debt Securities [Member]
Fair Value of Financial Instruments
Total assets measured at fair value	14,520	1,961
Fair Value, Measurements, Recurring [Member] \| Estimate of Fair Value Measurement [Member]
Fair Value of Financial Instruments
Total assets measured at fair value	39,453	76,022
Total liabilities measured at fair value	89
Fair Value, Measurements, Recurring [Member] \| Estimate of Fair Value Measurement [Member] \| Financing derivative
Fair Value of Financial Instruments
Total liabilities measured at fair value	89
Fair Value, Measurements, Recurring [Member] \| Estimate of Fair Value Measurement [Member] \| Money Market Funds [Member]
Fair Value of Financial Instruments
Total assets measured at fair value	9,663	53,511
Fair Value, Measurements, Recurring [Member] \| Estimate of Fair Value Measurement [Member] \| US Government Corporations and Agencies Securities [Member]
Fair Value of Financial Instruments
Total assets measured at fair value	13,770	12,301
Fair Value, Measurements, Recurring [Member] \| Estimate of Fair Value Measurement [Member] \| Commercial Paper [Member]
Fair Value of Financial Instruments
Total assets measured at fair value	1,500	8,249
Fair Value, Measurements, Recurring [Member] \| Estimate of Fair Value Measurement [Member] \| Corporate Debt Securities [Member]
Fair Value of Financial Instruments
Total assets measured at fair value	$ 14,520	$ 1,961