Summary of Significant Accounting Policies - Equity Method Investments - Additional Information (Details) $ in Thousands	3 Months Ended
Mar. 31, 2018 USD ($)
Equity securities \| Oragenics, Inc.
Schedule of Equity Method Investments [Line Items]
Unrealized appreciation (depreciation) in fair value of equity securities	$ (751)

The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of investments, not including unrealized gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, held at each balance sheet date and included in earnings for the period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration