XML 50 R36.htm IDEA: XBRL DOCUMENT v2.4.1.9
Summary of Fair Value Measurement of Financial Assets (Detail) (Short Term Investments and Cash Equivalents, USD $)
In Thousands, unless otherwise specified
Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Cash equivalents - Overnight Investments $ 1,623crv_CashCashEquivalentsAndInvestmentsFairValueDisclosure
Fair Value, Inputs, Level 2  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Cash equivalents - Overnight Investments $ 1,623crv_CashCashEquivalentsAndInvestmentsFairValueDisclosure
/ us-gaap_FairValueByAssetClassAxis
= crv_ShortTermInvestmentsAndCashEquivalentsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member