Collaboration Agreement - Governance Agreement - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2015
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Minimum target percentage of beneficial ownership to be maintain under governance agreement	35.00%
Governance Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of independent directors	3
Number of directors designated by partner	2
Number of chief executive officer	1
Period to be consider after the first commercial sale for restriction to acquire and sale of stock	12 months