Description of Business and Accounting Policies - Additional Information (Detail)		12 Months Ended
	Jul. 01, 2019 Segment	Dec. 31, 2019 USD ($) Deposit Segment shares	Dec. 31, 2018 USD ($) shares
Summary Of Business And Accounting Policies [Line Items]
Entity incorporation date		1994-07
Common stock equivalent shares excluded from computation of diluted per share amounts | shares		1,570,000	1,714,000
Number of restricted cash deposits		2
Number of deposit held as security on letter of credit		1
Letter of credit expiration year		2020
Number of deposit held as security on corporate credit card line		1
Operating lease expiration period		We lease office facilities, primarily under operating leases, which expire at various dates through 2027
Number of reportable segment | Segment	2	2
Research and development expense | $		$ 5,751,000	$ 8,629,000
Advertising expense | $		$ 154,000	$ 171,000
Office furniture and equipment [Member]
Summary Of Business And Accounting Policies [Line Items]
Leasehold improvements estimated useful life		3 years
Minimum [Member]
Summary Of Business And Accounting Policies [Line Items]
Intangible assets useful life range		1 year
Minimum [Member] | Leasehold improvements [Member]
Summary Of Business And Accounting Policies [Line Items]
Leasehold improvements estimated useful life		2 years
Maximum [Member]
Summary Of Business And Accounting Policies [Line Items]
Intangible assets useful life range		10 years
Maximum [Member] | Leasehold improvements [Member]
Summary Of Business And Accounting Policies [Line Items]
Leasehold improvements estimated useful life		10 years