CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net loss before noncontrolling interest	$ (12,186)	$ (10,814)
Other comprehensive income (loss):
Foreign currency translation adjustments	0	662
Unrealized foreign exchange loss on intercompany balance	0	(679)
Net unrealized gain on available-for-sale securities	0	26
Other comprehensive income	0	9
Comprehensive loss	(12,186)	(10,805)
Comprehensive loss attributable to noncontrolling interest	0	0
Comprehensive loss attributable to CTI	$ (12,186)	$ (10,805)