Organization and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	0 Months Ended	1 Months Ended	3 Months Ended		0 Months Ended
	Nov. 09, 2012 D	Oct. 31, 2012 D	Mar. 31, 2013	Nov. 08, 2012	Nov. 08, 2012 Glaxo Group Limited	Nov. 09, 2012 Glaxo Group Limited
Organization And Summary Of Significant Accounting Policies [Line Items]
Annual payment for inventory of gabapentin enacarbil in GSK's possession for six years beginning in 2016			$ 1,000,000
Proceed from issuance of common stock					$ 20,000,000	$ 20,000,000
Stock issued, shares					1,841,112	2,190,100
Stock issued, price per-shares					$ 10.863	$ 9.132
Percentage of stock issue price over average stock closing price	12.50%			12.50%
Common Stock Trading Days to be Considered For Valuation	10	10