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Technology Acquisition Agreement - Additional Information (Detail) - USD ($)	1 Months Ended		9 Months Ended
	May. 31, 2014	Jun. 30, 2007	Sep. 30, 2015
Technology Acquisition Agreement [Line Items]
Payment expensed as in-process research and development		$ 650,000
Mallinckrodt Plc [Member] \| Patented Technology
Technology Acquisition Agreement [Line Items]
Expected expiration of patent right			2030
Mallinckrodt Plc [Member] \| Rights and Patents Acquired from Questcor Pharmaceuticals Inc [Member] \| Maximum [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 Two And Three [Member] \| Mallinckrodt Plc [Member] \| Maximum [Member]
Technology Acquisition Agreement [Line Items]
Milestone payments contingent amount			$ 4,500,000
Development Target Two [Member] \| Mallinckrodt Plc [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 Plc [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 Plc [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