Stock Option Plans, Shares Reserved and Warrants (Details 2) - $ / shares		3 Months Ended	12 Months Ended
		Mar. 31, 2019	Dec. 31, 2018
RSU [Member]
Total RSUs		3,877,491	1,642,212
Board of Directors [Member]
Total RSUs	[1]	350,000	350,000
Price at grant date (in dollars per share)		$ 8.46	$ 8.46
Date of grant		May 25, 2016	May 25, 2016
Company Executives #1 [Member]
Total RSUs	[1]	950,000	950,000
Price at grant date (in dollars per share)		$ 3.50	$ 3.50
Date of grant		Mar. 01, 2017	Mar. 01, 2017
Company Executives #2 [Member]
Total RSUs	[2]	228,141	342,212
Price at grant date (in dollars per share)		$ 2.83	$ 2.83
Date of grant		Feb. 21, 2018	Feb. 21, 2018
Company Executives And Employees [Member]
Total RSUs	[3]	2,349,350
Price at grant date (in dollars per share)		$ 3.09
Date of grant		Jan. 30, 2019

[1] The RSUs will fully vest on the seventh anniversary of the date of grant if the recipient has provided continuous service or upon change of control or upon death or disability.

[2] The RSUs vest ratably annually over a period of three years if the recipient has provided continuous service or upon change of control or upon death or disability.

[3] The RSUs vest ratably quarterly over a period of three years if the recipient has provided continuous service or upon change of control or upon death or disability.