Debt - Components of Debt Obligations and Weighted Average Interest Rate (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Long-term debt, gross	$ 32,179	$ 33,694
Finance lease liability	165	189
Unaccreted discount and issuance costs	(271)	(324)
Current portion of long-term debt	3,026	3,232
Long-term debt, net of current portion	29,047	30,327
Total long-term debt, net of unaccreted discount and issuance costs	32,073	33,559
Line of credit \| Borrowing under Wells Fargo Credit Facility
Debt Instrument [Line Items]
Long-term debt, gross	$ 21,136	$ 21,030
Weighted average interest rate	1.96%	2.01%
Notes payable to banks \| Mitsubishi Bank loans
Debt Instrument [Line Items]
Long-term debt, gross	$ 6,655	$ 7,662
Notes payable to banks \| Mitsubishi Bank loans \| Minimum
Debt Instrument [Line Items]
Weighted average interest rate	1.07%	1.05%
Notes payable to banks \| Mitsubishi Bank loans \| Maximum
Debt Instrument [Line Items]
Weighted average interest rate	1.47%	1.45%
Notes payable to banks \| Mitsubishi Bank and Yamanashi Chuo Bank loan
Debt Instrument [Line Items]
Long-term debt, gross	$ 4,388	$ 5,002
Weighted average interest rate	1.08%	1.07%

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Amount of unamortized debt discount (premium) and debt issuance costs.

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- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

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- Definition

Present value of lessee's discounted obligation for lease payments from finance lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
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-URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918701-209980

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- Definition

Amount of long-term debt and lease obligation, classified as noncurrent.

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Amount of long-term debt and lease obligation, classified as current.

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- Definition

Amount of long-term debt and lease obligation, including portion classified as current.

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