Net Income (Loss) per Share - Reconciliation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Net income (loss) attributable to ION	$ 4,935	$ 1,699	$ (28,848)	$ (58,657)
Weighted average number of common shares outstanding (in shares)	11,890	11,786	11,862	11,269
Effect of dilutive stock awards	181	121	0	0
Weighted average number of diluted common shares outstanding (in shares)	12,071	11,907	11,862	11,269
Basic net income (loss) per share (usd per share)	$ 0.42	$ 0.14	$ (2.43)	$ (5.21)
Diluted net income (loss) per share (usd per share)	$ 0.41	$ 0.14	$ (2.43)	$ (5.21)