Investments Investments (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	May 17, 2017	Dec. 31, 2016
Investment [Line Items]
Operating Lease, Cost	$ 153,000	$ 335,000
Cash paid for investment			$ 6,000,000	$ 2,250,000
Unrealized Gain (Loss) on Investment - Warrants	(697,000)	(7,647,000)
Unrealized Gain (Loss) on Investments - Common Stock	$ 7,605,000	(33,450,000)
Percentage of ownership, Miso Robotics	30.00%
Maximum Investment in Veritone					$ 50,000,000
Secured Convertible Promissory Note						$ 20,000,000
Secured Promissory Note Advance					4,000,000
First Loan Warrant					$ 154,312
Debt Instrument, Convertible, Conversion Price					$ 13.61
Primary warrant shares					2,150,335
Common stock, shares outstanding	49,656,067		49,639,319
Cash paid for primary warrant exercise					$ 29,300,000
10% Warrant					809,400
Bridge Installment Shares					445,440
Bridge Warrant Share					156,720
Shares of Investment Sold	628,048		2,700,000
Loss on Sale of Investments	$ 5,590,000	0	$ 19,100,000
Investment warrants	1,367,000		2,064,000
Investment in common stock	4,116,000		5,395,000
Investments at fair value	5,483,000		7,459,000
Revenues	$ 3,387,000	$ 62,093,000
Earnings Per Share, Basic	$ (0.09)	$ (0.63)
Assets, Current	$ 195,522,000		201,472,000
Total assets	219,097,000		223,949,000
Current liabilities	31,347,000		31,035,000
Total liabilities	32,263,000		32,709,000
Stockholders' Equity Attributable to Parent	185,001,000		$ 189,393,000
Equity Method Investment, Ownership Percentage				23.00%
Realized Investment Gains (Losses)	(5,590,000)	$ 0
Net change in fair value investment	$ 1,318,000	$ (41,097,000)
Minimum [Member]
Investment [Line Items]
Sale of Stock, Price Per Share	$ 4.71		$ 4.95
Maximum [Member]
Investment [Line Items]
Sale of Stock, Price Per Share	$ 7.13		$ 10.44
Veritone [Member]
Investment [Line Items]
Common stock, shares outstanding					1,523,746
Common Stock [Member]
Investment [Line Items]
Investment Owned, Balance, Shares	791,473				4,119,521
Warrant [Member]
Investment [Line Items]
Investment Owned, Balance, Shares	1,120,432				1,120,432