Amortization of debt discount and end of term payment.

No definition available.

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Namespace Prefix:	rkda_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Collateralized debt obligation percentage.

+ References

No definition available.

+ Details

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Namespace Prefix:	rkda_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument end of term fee.

+ References

No definition available.

+ Details

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Namespace Prefix:	rkda_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Debt instrument prepayment fee.

+ References

No definition available.

+ Details

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Namespace Prefix:	rkda_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Liquidity ratio.

+ References

No definition available.

+ Details

Name:	rkda_LiquidityRatio
Namespace Prefix:	rkda_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of installments.

+ References

No definition available.

+ Details

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Namespace Prefix:	rkda_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Partially offset end of term fee previously amortized.

+ References

No definition available.

+ Details

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Namespace Prefix:	rkda_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Partially offset end of term fee previously amortized netting.

+ References

No definition available.

+ Details

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Namespace Prefix:	rkda_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Prepayment fee as of outstanding principal amount percentage.

+ References

No definition available.

+ Details

Name:	rkda_PrepaymentFeeAsOfOutstandingPrincipalAmountPercentage
Namespace Prefix:	rkda_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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

- 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=64930739&loc=d3e28878-108400

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

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

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ 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)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of payment greater than the preceding installment payments to be paid at final maturity date of debt.

+ References

No definition available.

+ Details

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

- Definition

Amount, before accumulated amortization, of debt issuance costs classified as current. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: 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=64930785&loc=d3e28555-108399

+ Details

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

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12317-112629

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

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-Paragraph 1
-Subparagraph (SX 210.9-04.9)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow to repay long-term debt that is wholly or partially secured by collateral. Excludes repayments of tax exempt secured debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

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Balance Type:	credit
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- Details

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- Details

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Debt - Term Loan - Additional Information (Detail)	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
Debt - Term Loan - Additional Information (Detail)	Jul. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($) Installment
Debt Instrument [Line Items]
Loss on extinguishment of debt		$ (900,000)		$ (900,000)
Repayment of accrued interest and prepayment fee		43,000	$ 331,000	$ 747,000	$ 985,000
Senior Secured Term Loan Facility [Member]
Debt Instrument [Line Items]
Debt instrument, face amount						$ 25,000,000
Repayment of term loan	$ 25,000,000
Debt instrument end-of-term fee	625,000
Debt instrument prepayment fee	$ 500,000
Number of installments \| Installment						36
Repayment date of outstanding principal amounts and accrued interest						Dec. 01, 2020
Additional term payment due on maturity of term loan						$ 625,000
Cash collateralized obligations				100.00%
Loss on extinguishment of debt				$ (1,100,000)
Deferred loan issuance fees		41,000		41,000
Partially offset end of term fee previously amortized				267,000
Partially offset end of term fee previously amortized netting				900,000
Repayment of accrued interest and prepayment fee		43,000	747,000	331,000	985,000
Amortization of debt discount and end of term payment		$ 0	$ 98,000	$ 50,000	$ 148,000
Senior Secured Term Loan Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Liquidity ratio				140.00%
Senior Secured Term Loan Facility [Member] \| Prepayment Occurs After December 29, 2016 but on or Prior to December 29, 2017 [Member]
Debt Instrument [Line Items]
Prepayment fee as of outstanding principal amount percentage						2.00%
Senior Secured Term Loan Facility [Member] \| Prepayment Occurs After December 29, 2017 [Member]
Debt Instrument [Line Items]
Prepayment fee as of outstanding principal amount percentage						1.00%
Senior Secured Term Loan Facility [Member] \| Prime Rate [Member]
Debt Instrument [Line Items]
Interest on the notes						0.90%