Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2022

Accounting Policies [Abstract]

Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]

Restricted cash and cash equivalents

Restricted cash as of September 30, 2021 represent funds that are restricted to satisfy any amount borrowed against the Company's Cash Collateral Security agreement with BMO Harris Bank N.A (Cash Collateral Security agreement). In June 2022, the Company replaced the former Cash Collateral Security agreement with an Investment Collateral Security agreement with BMO Harris Bank N.A (Investment Collateral Security agreement) where existing standby letters of credit are collateralized by amounts held in the Company's investment funds (see Note 10). 

The following table provides a reconciliation of cash, cash equivalents, and restricted cash and cash equivalents reported within the Condensed Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Condensed Consolidated Statements of Cash Flows:

	September 30,		September 30,
	2022		2021
Cash	$	23,856	$	35,161
Cash equivalents		226		—
Restricted cash and cash equivalents included in current assets		—		891
Restricted cash included in long-term assets		—		270
Total cash, cash equivalents, and restricted cash and cash equivalents shown in the Condensed Consolidated Statements of Cash Flows	$	24,082	$	36,322

Investment, Policy [Policy Text Block]

Investments

In June 2022, the Board of Directors approved a plan to invest up to $10,000 of excess capital in debt securities, or held in money market funds until such investments can be made, with BMO Harris Bank N.A (BMO Harris). A portion of the funds invested are restricted as collateral under the Investment Collateral Security agreement (see Note 10). At September 30, 2022, the amount of funds collateralized under the Investment Collateral Security agreement is $1,090 relating to existing standby letters of credit with varying maturity dates and expire no later than September 30, 2023.

We consider all highly liquid debt investments with original maturities from the date of purchase of three months or less as cash equivalents. Cash equivalents include investments in money market funds. Carrying value of cash equivalents approximates fair value due to the maturities of three months or less.

Our investments in debt securities consist of United States (US) Treasury securities, including Notes, Bonds, and Bills, and US Government Agency securities, which are designated as held-to-maturity (HTM) and stated at amortized cost. The Company has the positive intent and ability to hold these investments to maturity and does not expect to sell any debt securities before maturity to settle an obligation under the Investment Collateral Security agreement. The maturities of our HTM investments range from three to thirty-six months. HTM debt investments with original maturities of approximately three months or less from the date of purchase are classified within cash and cash equivalents. HTM debt investments with original maturities at the date of purchase greater than approximately three months and remaining maturities of less than one year are classified as short-term investments. HTM debt investments with remaining maturities beyond one year are classified as long-term investments. Interest income, including amortization of premium and accretion of discount, are included on the Condensed Consolidated Statements of Operations in Interest income under the effective yield method. Accrued interest is included in Prepaid expenses and other current assets on the Condensed Consolidated Balance Sheets. 

The following table provides the amortized cost, gross unrealized gains and losses, and fair value of our HTM debt securities at September 30, 2022:

Held-to-maturity debt securities:
Amortized cost	$	9,808
Gross unrecognized gains		—
Gross unrecognized losses		(161	)
Fair value	$	9,647

The following table provides the amortized cost and fair value of debt securities by maturities at September 30, 2022:

	Amortized Cost		Fair Value
Within one year	$	2,469	$	2,460
After one year through two years		3,937		3,866
After two years through three years		3,402		3,321
Total	$	9,808	$	9,647

Inventory, Policy [Policy Text Block]

Inventories

Inventories consist primarily of equipment constructed for resale and spare parts and are stated at the lower of cost or net realizable value, using the weighted-average cost method. At  September 30, 2022 and December 31, 2021, inventory included equipment constructed for resale of $208 and $227, respectively, and spare parts, net of reserves of $183 and $121, respectively. Usage is recorded in cost of sales in the period that parts were issued to a project, used to service equipment, or sold to customers. Inventories are periodically evaluated to identify obsolete or otherwise impaired parts and are written off when management determines usage is not probable. The Company estimates the balance of excess and obsolete inventory by analyzing inventory by age using last used and original purchase date and existing sales pipeline for which the inventory could be used.