As part of an agreement made in anticipation of a purchase of common stock from a shareholder of the reporting entity by a officer and director of the company, this amount represents the number of shares that were returned to the shareholder and subsequently sold to the CEO.

No definition available.

Note 9 - Stock-based Compensation (Details Textual) - USD ($)		1 Months Ended		12 Months Ended
	Jul. 08, 2016	Mar. 31, 2017	Jul. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period				7,000,000
Agreement for Anticipated Purchase of Common Stock, Number of Shares Returned to Shareholder	5,000,000				5,000,000
Allocated Share-based Compensation Expense				$ 15,000,000	$ 7,600,000	$ 3,000,000
Stock Issued During Period, Value, New Issues				12,550,000	188,000	1,982,000
Proceeds from Issuance of Common Stock				12,550,000	188,000	1,982,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized				$ 39,100,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition				2 years 32 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value				$ 115,100,000
Dennis Di Ricco [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period		7,000,000
The 13 Employees and Current and Perspective Board Members [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant		3,600,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		3 years
Share Price		$ 10.49
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value		$ 37,600,000
The 13 Employees and Current and Perspective Board Members [Member] \| Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term		4 years 273 days
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate		86.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate		2.02%
Chief Executive Officer [Member]
Allocated Share-based Compensation Expense			$ 4,990,000		$ 4,990,000	$ 499,000
Stock Issued During Period, Shares, New Issues						500,000
Stock Issued During Period, Value, New Issues						$ 500,000
Proceeds from Issuance of Common Stock						$ 1,000