The difference between the carrying value and the sale price of equity securities, not separately or otherwise categorized as trading or available-for-sale. This element includes investments in which the entity holds a small ownership stake (generally, less than 20% of the shares outstanding) and cannot exert significant influence.

No definition available.

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

Sale of Investment in Software Company (Details) - USD ($)			12 Months Ended
	Oct. 31, 2018	Jul. 06, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity Securities without Readily Determinable Fair Value [Line Items]
Gain on sale of BriefCam, Ltd.			$ 0	$ (41,000)	$ (6,602,000)
BriefCam, Canon Inc
Equity Securities without Readily Determinable Fair Value [Line Items]
Proceeds from Sale of Other Investments	$ 100,000	$ 9,700,000