Significant Accounting Policies - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Dec. 31, 2013 Segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Significant Accounting Policies [Line Items]
Allowance for doubtful accounts		$ 91,300	$ 96,600
Allowance for doubtful accounts, additions		0	33,600	$ 63,000
Write-offs of uncollectible accounts		5,000	0	0
Inventory reserves		2,200,000	2,200,000
Inventory reserves additions		800,000	200,000	200,000
Write-offs of inventory reserves		700,000	300,000	100,000
Impairment losses on long-lived assets		0	0
Deferred offering costs		$ 0	181,000
Number of reportable segments | Segment	1
Standard warranty period		12 months
Percentage used to determine discount for stand-alone sales (previous 12 months)		15.00%
Product warranty accrual period		1 year
Advertising costs		$ 5,300,000	2,600,000	$ 5,100,000
Guarantees and indemnifications liabilities		$ 0	$ 0
Manufacturing equipment
Significant Accounting Policies [Line Items]
Estimated useful lives of the assets		5 years
Prototype Systems
Significant Accounting Policies [Line Items]
Estimated useful lives of the assets		2 years
Computer equipment
Significant Accounting Policies [Line Items]
Estimated useful lives of the assets		3 years
Furniture and fixtures
Significant Accounting Policies [Line Items]
Estimated useful lives of the assets		5 years
Minimum
Significant Accounting Policies [Line Items]
Extended warranty period		12 months
Minimum | Lease and loaner instruments
Significant Accounting Policies [Line Items]
Estimated useful lives of the assets		1 year
Maximum
Significant Accounting Policies [Line Items]
Extended warranty period		36 months
Maximum | Lease and loaner instruments
Significant Accounting Policies [Line Items]
Estimated useful lives of the assets		5 years
Customer Concentration Risk | Total revenue | Minimum
Significant Accounting Policies [Line Items]
Concentration risk, percentage		13.00%
Product Concentration Risk | Total revenue | Instruments and Consumables
Significant Accounting Policies [Line Items]
Concentration risk, percentage		76.00%