Cash and cash equivalents held by foreign subsidiaries.

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Credit terms for trade receivables.

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Extended credit terms for trade receivables.

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Significant accounting policies line items.

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Unrecorded excess tax benefits in additional paid-in-capital account.

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Carrying amount as of the balance sheet date, net of allowance for doubtful accounts, of account and note receivables due from other than related parties.

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Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount of cumulative effect of the change in accounting principle or new accounting pronouncement on retained earnings or other components of equity or net assets in the statement of financial position as of the beginning of the earliest period presented.

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Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services.

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Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2017	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Significant Accounting Policies [Line Items]
Cash and cash equivalents held by foreign subsidiaries and branch offices		$ 7,300,000	$ 7,300,000
Minimum credit limit			30 days
Extended credit terms for trade receivables			60 days
Accounts receivable		14,323,000	$ 14,323,000	$ 9,435,000
Cumulative-effect adjustment to retained earnings		$ 400,000	$ 400,000
U.S. income tax rate	35.00%	21.00%	24.50%	35.00%	35.00%
Unrecorded excess tax benefits in additional paid-in-capital account			$ 0
Shipping and Handling
Significant Accounting Policies [Line Items]
Shipping and handling costs			500,000	$ 300,000	$ 400,000
Customer one
Significant Accounting Policies [Line Items]
Trade account and financing receivable due		$ 9,000,000	$ 9,000,000
Financing receivable				$ 8,100,000
Accounts receivable					$ 9,100,000
Customer Concentration Risk \| Customer one \| Sales Revenue, Net
Significant Accounting Policies [Line Items]
Percentage of company revenue			10.40%	17.80%	18.50%