Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Allowance for Doubtful Accounts [Member]      
Valuation and Qualifying Accounts Disclosure [Line Items]      
Balance at beginning of period $ 1,871 $ 1,943 $ 1,441
Additions charged to costs and expenses 1,809 524 803
Deductions (864) (414) (260)
Other additions or deductions (1) (182) (41)
Balance at end of period 2,815 1,871 1,943
Reserve for Credit Memos [Member]      
Valuation and Qualifying Accounts Disclosure [Line Items]      
Balance at beginning of period 455 428 672
Additions charged to costs and expenses (674) 437 408
Deductions   (408) (652)
Deductions 613    
Other additions or deductions 1 (2) 0
Balance at end of period 395 455 428
Slow-Moving and Obsolete Inventory Reserve [Member]      
Valuation and Qualifying Accounts Disclosure [Line Items]      
Balance at beginning of period 10,230 9,183 8,075
Additions charged to costs and expenses 2,825 2,477 2,244
Deductions (1,408) (1,509) (701)
Other additions or deductions (87) 79 (435)
Balance at end of period 11,560 10,230 9,183
Accrued Product Warranty [Member]      
Valuation and Qualifying Accounts Disclosure [Line Items]      
Balance at beginning of period 714 892 1,140
Additions charged to costs and expenses 649 74 (45)
Deductions (269) (158) (133)
Other additions or deductions (36) (94) (70)
Balance at end of period 1,058 714 892
Foreign Net Operating Loss Tax Carryforwards [Member]      
Valuation and Qualifying Accounts Disclosure [Line Items]      
Balance at beginning of period 5,209 3,614 1,420
Additions charged to costs and expenses 346 2,105 2,553
Deductions (1,175) (287) (232)
Other additions or deductions (575) (223) (127)
Balance at end of period $ 3,805 $ 5,209 $ 3,614