XML 105 R41.htm IDEA: XBRL DOCUMENT v2.4.1.9
Significant Accounting Policies - Additional Information (Detail) (USD $)
3 Months Ended 12 Months Ended
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2013
Dec. 31, 2014
Segment
Dec. 31, 2013
Dec. 31, 2012
Disclosure - Significant Accounting Policies - Additional Information (Detail) [Line Items]            
Revenue $ 33,000us-gaap_Revenues $ 47,000us-gaap_Revenues $ 6,000us-gaap_Revenues $ 80,000us-gaap_Revenues $ 6,000us-gaap_Revenues $ 625,000us-gaap_Revenues
Number of operating segments       1us-gaap_NumberOfOperatingSegments    
Restricted cash     117,000us-gaap_RestrictedCashAndCashEquivalentsNoncurrent 117,000us-gaap_RestrictedCashAndCashEquivalentsNoncurrent 117,000us-gaap_RestrictedCashAndCashEquivalentsNoncurrent  
Facility lease scheduled expiration period       2016-02    
Sydney, NSW [Member]            
Disclosure - Significant Accounting Policies - Additional Information (Detail) [Line Items]            
Revenue       0us-gaap_Revenues
/ us-gaap_StatementGeographicalAxis
= ceru_SydneyMember
   
Long-lived assets       $ 0us-gaap_NoncurrentAssets
/ us-gaap_StatementGeographicalAxis
= ceru_SydneyMember