BIOLASE, Inc. Annual report pursuant to Section 13 and 15(d)

Consolidated Valuation and Qualifying Accounts and Reserves (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for doubtful accounts
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 1,209	$ 1,765	$ 1,711
Charges (Reversals) to Cost or Expenses	(401)	(438)	86
Deductions	(6)	(118)	(32)
Balance at End of Year	802	1,209	1,765
Allowance for sales returns
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	210	210	110
Charges (Reversals) to Cost or Expenses			100
Balance at End of Year	210	210	210
Allowance for tax valuation
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	54,310	49,514	42,069
Charges (Reversals) to Cost or Expenses	(13,444)	4,796	7,445
Balance at End of Year	$ 40,866	$ 54,310	$ 49,514