Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019 USD ($) Customer Segment	Dec. 31, 2018 USD ($) Customer	Dec. 31, 2017 USD ($)	Jan. 01, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Description of payment of customer invoice contract	The Company invoices its customers based upon the terms in the contracts, which generally requires payment 30 to 60 days from the date of invoice.
Contract asset	$ 0	$ 0
Revenue recognized, that were included in deferred product revenue	$ 500,000
Application of an optional exemption not to disclose the value of unsatisfied performance obligations	true
Number of major customers representing outstanding trade receivables | Customer	3	2
Protracted length of inventory	1 year
Inventory valuation reserves	$ 100,000	$ 300,000
Accumulated amortization intangible assets	$ 1,900,000	1,700,000
Estimated useful life of intangible assets	10 years
Number of reportable segments | Segment	1
Impairment charges acquired intangible assets	$ 0	0	$ 0
Period of warranty	1 year
Warranty claim liability	$ 0	0
Operating lease right-of-use assets	14,122,000
Operating lease liabilities – current	1,613,000
ASU 2016-02
Summary Of Significant Accounting Policies [Line Items]
Operating lease right-of-use assets				$ 2,400,000
Operating lease liabilities – current				$ 2,400,000
Leasehold Improvements
Summary Of Significant Accounting Policies [Line Items]
Capitalized construction-in-progress costs	0	6,900,000
Prepaid and Other Current Assets
Summary Of Significant Accounting Policies [Line Items]
Receivables related to office building	$ 0	$ 1,200,000
Trade Accounts Receivable | Customer Concentration Risk
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	56.00%	50.00%
Minimum
Summary Of Significant Accounting Policies [Line Items]
Payment of customer invoice contract period	30 days
Shelf lives of inventory	18 months
Estimated useful life of property and equipment	3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Payment of customer invoice contract period	60 days
Shelf lives of inventory	24 months
Estimated useful life of property and equipment	5 years