Related Party Transactions - Additional Information (Detail) - USD ($)	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Aston Biopharma Ltd [Member]
Related Party Transaction [Line Items]
Compensation paid	$ 137,000	$ 190,000
Angiogene [Member]
Related Party Transaction [Line Items]
Noncontrolling interest, ownership percentage by non controlling owners	33.00%
Amount paid in connection with license	$ 0	$ 75,000

Costs incurred and are directly related to generating license revenue. Licensing arrangements include, but are not limited to, rights to use a patent, copyright, technology, manufacturing process, software or trademark.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Name:	us-gaap_LicenseCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration