Quarterly report pursuant to Section 13 or 15(d)

Business Combinations - Unaudited Pro forma Financial Information (Details)

v3.8.0.1
Business Combinations - Unaudited Pro forma Financial Information (Details) - Otometric - 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
Business Acquisition [Line Items]        
Revenue $ 122,643 $ 118,431 $ 369,531 $ 356,769
Net income (loss) $ (6,113) $ 3,494 $ (6,398) $ 3,311
Earnings (loss) per share:        
Basic (usd per share) $ (0.19) $ 0.11 $ (0.20) $ 0.10
Diluted (usd per share) $ (0.19) $ 0.11 $ (0.20) $ 0.10
Weighted average shares used in the calculation of earnings per share:        
Basic (shares) 32,593 32,388 32,536 32,476
Diluted (shares) 32,593 32,981 32,536 33,077