Stock Options (Details 3)	12 Months Ended
Dec. 31, 2017 $ / shares shares
Number of Shares Subject to Outstanding Options \| shares	545,000
Weighted Average Contractual Life (years)	8 years 7 months 10 days
Weighted Average Exercise Price	$ 3.09
Number of Shares Subject To Options Exercise \| shares	390,000
Weighted Average Remaining Contractual Life (Years)	8 years 5 months 20 days
Weighted Average Exercise Price	$ 2.8
Exercise Price Range One [Member]
Range of Exercise Prices	$ 0.8
Number of Shares Subject to Outstanding Options \| shares	10,000
Weighted Average Contractual Life (years)	6 years 7 months 13 days
Weighted Average Exercise Price	$ 0.8
Number of Shares Subject To Options Exercise \| shares	10,000
Weighted Average Remaining Contractual Life (Years)	6 years 7 months 13 days
Weighted Average Exercise Price	$ 0.8
Exercise Price Range Two [Member]
Range of Exercise Prices	$ 1.05
Number of Shares Subject to Outstanding Options \| shares	55,000
Weighted Average Contractual Life (years)	6 years 2 months 30 days
Weighted Average Exercise Price	$ 1.05
Number of Shares Subject To Options Exercise \| shares	35,000
Weighted Average Remaining Contractual Life (Years)	6 years 2 months 30 days
Weighted Average Exercise Price	$ 1.05
Exercise Price Range Three [Member]
Range of Exercise Prices	$ 1.25
Number of Shares Subject to Outstanding Options \| shares	7,500
Weighted Average Contractual Life (years)	7 years 5 months 16 days
Weighted Average Exercise Price	$ 1.25
Number of Shares Subject To Options Exercise \| shares	7,500
Weighted Average Remaining Contractual Life (Years)	7 years 5 months 16 days
Weighted Average Exercise Price	$ 1.25
Exercise Price Range Four [Member]
Range of Exercise Prices	$ 1.34
Number of Shares Subject to Outstanding Options \| shares	7,500
Weighted Average Contractual Life (years)	7 years 6 months
Weighted Average Exercise Price	$ 1.34
Number of Shares Subject To Options Exercise \| shares	7,500
Weighted Average Remaining Contractual Life (Years)	7 years 6 months
Weighted Average Exercise Price	$ 1.34
Exercise Price Range Five [Member]
Range of Exercise Prices	$ 1.65
Number of Shares Subject to Outstanding Options \| shares	10,000
Weighted Average Contractual Life (years)	7 years 10 months 3 days
Weighted Average Exercise Price	$ 1.65
Number of Shares Subject To Options Exercise \| shares	10,000
Weighted Average Remaining Contractual Life (Years)	7 years 10 months 3 days
Weighted Average Exercise Price	$ 1.65
Exercise Price Range Six [Member]
Range of Exercise Prices	$ 1.7
Number of Shares Subject to Outstanding Options \| shares	7,500
Weighted Average Contractual Life (years)	7 years 9 months 14 days
Weighted Average Exercise Price	$ 1.7
Number of Shares Subject To Options Exercise \| shares	7,500
Weighted Average Remaining Contractual Life (Years)	7 years 9 months 14 days
Weighted Average Exercise Price	$ 1.7
Exercise Price Range Seven [Member]
Range of Exercise Prices	$ 1.91
Number of Shares Subject to Outstanding Options \| shares	130,000
Weighted Average Contractual Life (years)	8 years 2 months 16 days
Weighted Average Exercise Price	$ 1.91
Number of Shares Subject To Options Exercise \| shares	130,000
Weighted Average Remaining Contractual Life (Years)	8 years 2 months 16 days
Weighted Average Exercise Price	$ 1.91
Exercise Price Range Eight [Member]
Range of Exercise Prices	$ 2.28
Number of Shares Subject to Outstanding Options \| shares	7,500
Weighted Average Contractual Life (years)	8 years 6 months 18 days
Weighted Average Exercise Price	$ 2.28
Number of Shares Subject To Options Exercise \| shares	7,500
Weighted Average Remaining Contractual Life (Years)	8 years 6 months 18 days
Weighted Average Exercise Price	$ 2.28
Exercise Price Range Nine [Member]
Range of Exercise Prices	$ 4.2
Number of Shares Subject to Outstanding Options \| shares	310,000
Weighted Average Contractual Life (years)	9 years 4 months 9 days
Weighted Average Exercise Price	$ 4.2
Number of Shares Subject To Options Exercise \| shares	175,000
Weighted Average Remaining Contractual Life (Years)	9 years 4 months 9 days
Weighted Average Exercise Price	$ 4.2

Custom Element.

No definition available.

Name:	rcar_RangeOfExercisePricesWarrant
Namespace Prefix:	rcar_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(iii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average remaining contractual term of exercisable stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(2)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_StatementEquityComponentsAxis=rcar_ExercisePriceRangeOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=rcar_ExercisePriceRangeTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=rcar_ExercisePriceRangeThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=rcar_ExercisePriceRangeFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=rcar_ExercisePriceRangeFiveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=rcar_ExercisePriceRangeSixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=rcar_ExercisePriceRangeSevenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=rcar_ExercisePriceRangeEightMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=rcar_ExercisePriceRangeNineMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: