Organization and Summary of Significant Accounting Policies - Summary of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Inventory receipts	$ 3,049	$ 1,431
Payroll and other employee benefits	1,083	1,654
Paid time off	1,028	855
Professional fees and contractors	316	246
Warranties	285	444
Operating leases	$ 269	$ 282
Operating Lease Liability Current Statement Of Financial Position Extensible List	us-gaap:AccruedLiabilitiesCurrent	us-gaap:AccruedLiabilitiesCurrent
Deferred revenues	$ 242	$ 241
Employee stock purchase plan	224	228
Income and sales taxes	185	133
Real estate taxes	155	152
Customer refunds for estimated returns	146	147
Finance leases	68	77
Restructuring	15	45
Short-term incentive plan	0	2,504
Leasehold improvements	0	702
Other	251	241
Total	$ 7,316	$ 9,382