Stockholders' (Deficit) Equity - Additional Information (Detail) - USD ($) $ in Millions			3 Months Ended		9 Months Ended
	Nov. 05, 2019	Oct. 29, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	May 10, 2018	May 09, 2018
Stockholders Equity [Line Items]
Preferred stock, shares issued			0		0		0
Description of reverse stock split					At BIOLASE’s annual meeting of stockholders on May 9, 2018 (the “2018 Annual Meeting”), BIOLASE stockholders approved an amendment to BIOLASE’s Restated Certificate of Incorporation, as amended, to effect the Reverse Stock Split and on May 10, 2018, the Company filed an amendment (the “Amendment”) to its Restated Certificate of Incorporation, as amended, with the Secretary of State of the State of Delaware to effect the Reverse Stock Split, effective as of 11:59 p.m. on May 10, 2018. The Amendment also reduced the authorized shares of common stock from 200,000,000 shares to 40,000,000 shares. Prior year share and per share amounts have been adjusted to reflect the impact of the Reverse Stock Split.
Common stock, shares authorized			40,000		40,000		40,000	40,000,000	200,000,000
Compensation expense related to stock options			$ 0.8	$ 0.5	$ 1.9	$ 1.9
Total unrecognized compensation expense			$ 2.3		$ 2.3
Unrecognized share based compensation expense to be recognized over weighted-average period					1 year 8 months 8 days
Outstanding stock options, RSUs and warrants excluded from diluted loss per share			5,600,000	3,200,000	5,600,000	3,200,000
Restricted Stock Units (RSUs)
Stockholders Equity [Line Items]
Granted			1,900,000		2,200,000
2002 Stock Incentive Plan
Stockholders Equity [Line Items]
Common stock authorized for issuance			3,100,000		3,100,000
Common stock issued pursuant to options exercised					1,000,000
Options and restricted stock units outstanding			1,300,000		1,300,000
Options available for future grants			0		0
2018 Long-Term Incentive Plan
Stockholders Equity [Line Items]
Common stock authorized for issuance			5,000,000		5,000,000
Options and restricted stock units outstanding			3,900,000		3,900,000
Options available for future grants			1,100,000		1,100,000
Subsequent Event
Stockholders Equity [Line Items]
Net proceeds from issuance of shares after deducting underwriter discounts and other fees and expenses	$ 8.4	$ 7.8
Subsequent Event | Underwritten Public Offering | Common Stock
Stockholders Equity [Line Items]
Shares issued		7,820,000
Subsequent Event | Private Placement | Series E Participating Convertible Preferred Stock
Stockholders Equity [Line Items]
Preferred stock, shares issued		69,695