Note 4 - Revenue From Contracts With Customers (Details Textual) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017
Contract with Customer, Cumulative Catch-up Adjustment to Revenue, Change in Estimate of Transaction Price and Input Costs	$ (445,000)	$ (495,000)
Increase (Decrease) in Contract with Customer, Asset		(3,082,808)	$ 430,568
Increase (Decrease) in Contract with Customer, Liability		$ (187,051)	$ (2,277,718)

Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in estimate of transaction price and input costs.

No definition available.

+ Details

Name:	cvv_ContractWithCustomerCumulativeCatchupAdjustmentToRevenueChangeInEstimateOfTransactionPriceAndInputCosts
Namespace Prefix:	cvv_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of increase (decrease) in right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

+ Details

Name:	us-gaap_IncreaseDecreaseInContractWithCustomerAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of increase (decrease) in obligation to transfer good or service to customer for which consideration has been received or is receivable.

+ References

+ Details

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