UNAUDITED SUPPLEMENTARY DATA (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
UNAUDITED SUPPLEMENTARY DATA
Loss from operations	$ (804)	$ (2,785)	$ (2,064)	$ (1,402)	$ (1,904)	$ (2,927)	$ (2,880)	$ (2,631)	$ (7,055)	$ (10,342)
Other income/loss									2,885
Interest expense	(207)	(196)	(387)	(55)	(201)	(186)	(225)	(162)	(845)	(774)
Consolidated net loss	(1,011)	(2,981)	(2,451)	(1,457)	(2,105)	(3,113)	(3,105)	(2,793)	(7,900)	(11,116)
Net loss attributable to GMI	$ (1,005)	$ (2,976)	$ (2,476)	$ (1,421)	$ (2,171)	$ (3,033)	$ (2,931)	$ (2,609)	$ (7,878)	$ (10,744)
Basic net income/(loss) per share	$ (0.01)	$ (0.02)	$ (0.02)	$ (0.01)	$ (0.02)	$ (0.02)	$ (0.02)	$ (0.02)