Technology Acquisition Agreement - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended	1 Months Ended
	Jun. 30, 2007	Dec. 31, 2014	May 31, 2014
Technology Acquisition Agreement [Line Items]
Payment expensed as in-process research and development	$ 650,000
Mallinckrodt [Member] | Patented Technology
Technology Acquisition Agreement [Line Items]
Expected expiration of patent right		2030
Mallinckrodt [Member] | Rights and Patents Acquired from Questcor Pharmaceuticals Inc [Member]
Technology Acquisition Agreement [Line Items]
Milestone payments contingent amount		51,500,000
Development Target One [Member] | Rights and Patents Acquired from Questcor Pharmaceuticals Inc [Member]
Technology Acquisition Agreement [Line Items]
Milestone payment			500,000
Development targets description		Upon the initiation of the first patient dosing in the Company’s Phase 3 clinical trial for EVK-001
Development Target One, Two And Three [Member] | Mallinckrodt [Member]
Technology Acquisition Agreement [Line Items]
Milestone payments contingent amount		4,500,000
Development Target Two [Member] | Mallinckrodt [Member]
Technology Acquisition Agreement [Line Items]
Development targets description		Upon the FDA’s acceptance for review of a new drug application for EVK-001
Milestone payments contingent amount		1,500,000
Development Target Three [Member] | Mallinckrodt [Member]
Technology Acquisition Agreement [Line Items]
Development targets description		Upon the FDA’s approval of EVK-001
Milestone payments contingent amount		3,000,000
Development Target Four [Member] | Mallinckrodt [Member] | Patented Technology
Technology Acquisition Agreement [Line Items]
Development targets description		Depend on EVK-001’s commercial success and will only apply if EVK-001 receives regulatory approval. In addition, the Company will be required to pay to Mallinckrodt a low single digit royalty on net sales of EVK-001.
Milestone payments contingent amount		47,000,000