EMCORE (EMKR) 10-K 3 Dec 21 2021 FY Annual report Financial data

Cover

Cover - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Nov. 29, 2021	Mar. 31, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-36632
Entity Registrant Name	EMCORE Corp
Entity Incorporation, State or Country Code	NJ
Entity Tax Identification Number	22-2746503
Entity Address, Address Line One	2015 W. Chestnut Street
Entity Address, City or Town	Alhambra
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	91803
City Area Code	626
Local Phone Number	293-3400
Title of 12(b) Security	Common stock, no par value
Trading Symbol	EMKR
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 199
Entity Common Stock, Shares Outstanding		36,990,099
Documents Incorporated by Reference	In accordance with General Instruction G(3) of Form 10-K, certain information required by Part III hereof will either be incorporated into this Annual Report on Form 10-K by reference to the Definitive Proxy Statement for the Annual Meeting of Shareholders filed within 120 days of the fiscal year ended September 30, 2021 or will be included in an amendment to this Annual Report on Form 10-K filed within 120 days of September 30, 2021.
Entity Central Index Key	0000808326
Current Fiscal Year End Date	--09-30
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2021
Amendment Flag	false

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenue	$ 158,444	$ 110,128	$ 87,265
Cost of revenue	96,956	74,546	72,176
Gross profit	61,488	35,582	15,089
Operating expense:
Selling, general, and administrative	24,544	24,631	32,080
Research and development	17,448	20,269	19,443
Loss (gain) on sale of assets	515	(2,284)	(302)
Total operating expense	42,507	42,616	51,221
Operating income (loss)	18,981	(7,034)	(36,132)
Other income:
Gain on extinguishment of debt	6,561	0	0
Interest income (expense), net	466	(104)	629
Foreign exchange gain (loss)	207	198	(427)
Total other income	7,234	94	202
Income (loss) before income tax expense	26,215	(6,940)	(35,930)
Income tax expense	(572)	(60)	(54)
Net income (loss)	25,643	(7,000)	(35,984)
Foreign exchange translation adjustment	(231)	(32)	65
Comprehensive income (loss)	$ 25,412	$ (7,032)	$ (35,919)
Per share data:
Net income (loss) income per basic share (in dollars per share)	$ 0.75	$ (0.24)	$ (1.29)
Weighted-average number of basic shares outstanding (in shares)	34,020	29,136	27,983
Net income (loss) per diluted share (in dollars per share)	$ 0.72	$ (0.24)	$ (1.29)
Weighted-average number of diluted shares outstanding (in shares)	35,789	29,136	27,983

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Current assets:
Cash and cash equivalents	$ 71,621	$ 30,390
Restricted cash	61	148
Accounts receivable, net of allowance of $260 and $227, respectively	31,849	25,324
Contract assets	361	1,566
Inventory	32,309	25,525
Prepaid expenses and other current assets	6,877	5,589
Assets held for sale	1,241	1,568
Total current assets	144,319	90,110
Property, plant, and equipment, net	22,544	21,052
Goodwill	69	69
Operating lease right-of-use assets	13,489	14,566
Other intangible assets, net	167	202
Other non-current assets	225	242
Total assets	180,813	126,241
Current liabilities:
Accounts payable	16,686	16,484
Accrued expenses and other current liabilities	9,936	11,577
Operating lease liabilities - current	1,198	992
Total current liabilities	27,820	29,053
PPP Loan liability - non-current	0	6,488
Operating lease liabilities - non-current	12,684	13,735
Asset retirement obligations	2,049	2,022
Other long-term liabilities	794	794
Total liabilities	43,347	52,092
Commitments and contingencies (Note 11)
Shareholders’ equity:
Common stock, no par value, 50,000 shares authorized; 43,890 shares issued and 36,984 shares outstanding as of September 30, 2021; 36,461 shares issued and 29,551 shares outstanding as of September 30, 2020	782,266	744,361
Treasury stock at cost; 6,906 shares	(47,721)	(47,721)
Accumulated other comprehensive income	687	918
Accumulated deficit	(597,766)	(623,409)
Total shareholders’ equity	137,466	74,149
Total liabilities and shareholders’ equity	$ 180,813	$ 126,241

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Statement of Financial Position [Abstract]
Allowance for credit loss	$ 260	$ 227
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	43,890,000	36,461,000
Common stock, shares outstanding (in shares)	36,984,000	29,551,000
Treasury stock, shares held (in shares)	6,906,000	6,906,000

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Accumulated Other Comprehensive Income	Accumulated Deficit
Beginning balance (in shares) at Sep. 30, 2018		27,577,000
Shares of common stock
Stock-based compensation (in shares)		307,000
Stock option exercises (in shares)		1,000
Issuance of common stock for acquisition (in shares)		811,000
Issuance of restricted stock units (shares)		0
Issuance of common stock - ESPP (in shares)		197,000
Sale of common stock (in shares)		0
Ending balance (in shares) at Sep. 30, 2019		28,893,000
Balance, beginning of period at Sep. 30, 2018		$ 734,066	$ (47,721)	$ 885	$ (580,425)
Shares of common stock
Stock-based compensation		2,607
Stock option exercises		1
Tax withholding paid on behalf of employees for stock-based awards		(203)
Issuance of common stock for acquisition		2,951
Issuance of restricted stock units		0
Issuance of common stock - ESPP		504
Sale of common stock, net of offering costs		0
Translation adjustment	$ 65			65
Net income (loss)	(35,984)				(35,984)
Balance, end of period at Sep. 30, 2019	$ 76,746	$ 739,926	(47,721)	950	(616,409)
Shares of common stock
Stock-based compensation (in shares)		309,000
Stock option exercises (in shares)		1,000
Issuance of common stock for acquisition (in shares)		0
Issuance of restricted stock units (shares)		116,000
Issuance of common stock - ESPP (in shares)		231,000
Sale of common stock (in shares)		0
Ending balance (in shares) at Sep. 30, 2020	29,551,000	29,550,000
Shares of common stock
Stock-based compensation		$ 3,517
Stock option exercises		2
Tax withholding paid on behalf of employees for stock-based awards		(111)
Issuance of common stock for acquisition		0
Issuance of restricted stock units		410
Issuance of common stock - ESPP		617
Sale of common stock, net of offering costs		0
Translation adjustment	$ (32)			(32)
Net income (loss)	(7,000)				(7,000)
Balance, end of period at Sep. 30, 2020	$ 74,149	$ 744,361	(47,721)	918	(623,409)
Shares of common stock
Stock-based compensation (in shares)		572,000
Stock option exercises (in shares)	15,025	15,000
Issuance of common stock for acquisition (in shares)		0
Issuance of restricted stock units (shares)		0
Issuance of common stock - ESPP (in shares)		192,000
Sale of common stock (in shares)		6,655,000
Ending balance (in shares) at Sep. 30, 2021	36,984,000	36,984,000
Shares of common stock
Stock-based compensation		$ 4,180
Stock option exercises		77
Tax withholding paid on behalf of employees for stock-based awards		(260)
Issuance of common stock for acquisition		0
Issuance of restricted stock units		0
Issuance of common stock - ESPP		767
Sale of common stock, net of offering costs		33,141
Translation adjustment	$ (231)			(231)
Net income (loss)	25,643				25,643
Balance, end of period at Sep. 30, 2021	$ 137,466	$ 782,266	$ (47,721)	$ 687	$ (597,766)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income (loss)	$ 25,643	$ (7,000)	$ (35,984)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization expense	4,061	5,484	7,142
Stock-based compensation expense	4,180	3,517	2,607
Provision adjustments related to doubtful accounts	33	188	62
Provision adjustments related to product warranty	322	373	186
Loss (gain) on disposal of property, plant and equipment	515	(2,284)	(302)
Other	(658)	(342)	464
Total non-cash adjustments	8,453	6,936	10,159
Changes in operating assets and liabilities:
Accounts receivable and contract assets	(5,348)	(7,518)	3,980
Inventory	(6,326)	(1,226)	6,486
Other assets	(1,500)	(13,465)	(238)
Accounts payable	(420)	6,171	(4,539)
Accrued expenses and other current liabilities	(9,349)	12,210	4,985
Total change in operating assets and liabilities	(22,943)	(3,828)	10,674
Net cash provided by (used) in operating activities	11,153	(3,892)	(15,151)
Cash flows from investing activities:
Purchase of equipment	(5,358)	(4,516)	(10,790)
Acquisition of business, net of cash acquired	0	0	(21,483)
Proceeds from future sale of assets	834	0	0
Proceeds from disposal of property, plant and equipment	687	15,403	470
Net cash (used in) provided by investing activities	(3,837)	10,887	(31,803)
Cash flows from financing activities:
Proceeds from PPP Loan	0	6,488	0
Net (payments) proceeds from borrowings of credit facilities	0	(5,497)	5,497
Proceeds from employee stock purchase plans and exercise of equity awards	844	619	505
Proceeds from sale of common stock	35,937	0	0
Issuance cost associated with sale of common stock	(2,796)	0	0
Taxes paid related to net share settlement of equity awards	(260)	(111)	(203)
Net cash provided by financing activities	33,725	1,499	5,799
Effect of exchange rate changes provided by foreign currency	103	67	(63)
Net increase (decrease) in cash, cash equivalents and restricted cash	41,144	8,561	(41,218)
Cash, cash equivalents and restricted cash at beginning of period	30,538	21,977	63,195
Cash, cash equivalents and restricted cash at end of period	71,682	30,538	21,977
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid during the period for interest	61	113	126
Cash paid during the period for income taxes	975	63	68
NON-CASH INVESTING AND FINANCING ACTIVITIES
Changes in accounts payable related to purchases of equipment	360	(520)	(180)
Restricted stock units issued in settlement of bonus	$ 0	$ 410	$ 0

Description of Business

Description of Business	12 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of BusinessEMCORE Corporation (referred to herein, together with its subsidiaries, as the “Company,” “we,” “our,” or “EMCORE”) is a leading provider of sensors for navigation in the aerospace and defense market as well as a manufacturer of lasers and optical subsystems for use in the Cable TV ("CATV") industry. EMCORE pioneered the linear fiber optic transmission technology that enabled the world’s first delivery of CATV directly on fiber, and today is a leading provider of advanced products that enable communications systems and service providers to meet growing demand for increased bandwidth and connectivity. The technology at the heart of our broadband communications products is shared with our fiber optic gyroscope (“FOG”) and inertial sensors to provide the aerospace and defense markets with state-of-the-art navigation systems technology. With the acquisition of Systron Donner Inertial, Inc. ("SDI"), a navigation systems provider with a scalable, chip-based platform for higher volume gyro applications utilizing quartz micro-electromechanical system ("QMEMS") technology, in June 2019, EMCORE further expanded its portfolio of gyros and inertial sensors with SDI’s QMEMS gyro and accelerometer technology. EMCORE has fully vertically-integrated manufacturing capability through our indium phosphide ("InP") compound semiconductor wafer fabrication facility at our headquarters in Alhambra, CA, and through our quartz processing and sensor manufacturing facility in Concord, CA. These facilities support EMCORE’s vertically-integrated manufacturing strategy for quartz and FOG products, for navigation systems, and for our chip, laser, transmitter, and receiver products for broadband applications. With both analog and digital circuits on multiple chips, or even a single chip, the value of Mixed-Signal device solutions is often substantially greater than traditional digital applications and requires a specialized expertise held by EMCORE which is unique in the optics industry.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Principles of Consolidation The consolidated financial statements have been prepared in accordance with U.S. GAAP and include the assets, liabilities, shareholders’ equity, and operating results of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The Company is not the primary beneficiary of, nor do we hold a significant variable interest in, any variable interest entity. Going Concern Basis The consolidated financial statements included herein have been prepared on a going concern basis, which contemplates continuity of operations and the realization of assets and the repayment of liabilities in the ordinary course of business. Management evaluated the significance of the Company’s recent operating losses and determined that the Company’s current cash on hand, operating plan, and sources of capital will be sufficient for the Company to continue as a going concern. The Company has taken a number of actions to continue to support its operations and meet its obligations, including headcount and cost reductions, monetization of certain fixed assets and real estate, and entering into financing activities. The Company believes that its existing liquidity will be sufficient to meet anticipated cash needs for at least the next 12 months from the issuance date of these financial statements. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities, as of the date of the financial statements, and the reported amounts of revenue and expenses during the reported period. Such estimates include accounts receivable; inventories; goodwill; long-lived assets; product warranty liabilities; legal contingencies; and income taxes. We develop estimates based on historical experience and on various assumptions about the future that are believed to be reasonable based on the best information available to us. Our reported financial position or results of operations may be materially different under changed conditions or when using different estimates and assumptions, particularly with respect to significant accounting policies. In the event that estimates or assumptions prove to differ from actual results, adjustments are made in subsequent periods to reflect more current information. Concentration of Credit Risk Financial instruments that may subject us to concentrations of credit risk consist primarily of accounts receivable. When necessary, we perform credit evaluations on customers’ financial condition and occasionally we request deposits in advance of shipping product to customers. These financial evaluations require significant judgment and are based on a variety of factors including, but not limited to, current economic trends, historical payment patterns, bad debt write-off experience, and financial review of the particular customer. Cash and Cash Equivalents Cash and cash equivalents consists primarily of bank deposits and highly liquid short-term investments with a maturity of three months or less at the time of purchase. Restricted Cash Restricted cash represents recently deposited cash that is temporarily restricted by our bank in accordance with the terms of the outstanding credit facility. Accounts Receivable We regularly evaluate the collectability of accounts receivable and maintain allowances for doubtful accounts for estimated losses resulting from the inability of customers to meet their financial obligations to us. The allowance is based on the age of receivables and a specific identification of receivables considered at risk of collection. We classify charges associated with the allowance for doubtful accounts as selling, general, and administrative expense. Inventory Inventory is stated at the lower of cost or net realizable value (first-in, first-out). Inventory that is expected to be used within the next 12 months is classified as current inventory. We write-down inventory once it has been determined that conditions exist that may not allow the inventory to be sold for its intended purpose or the inventory is determined to be excess or obsolete based on assumptions about future demand and market conditions. The charge related to inventory write-downs is recorded as cost of revenue. We evaluate inventory levels at least quarterly against an estimate of future demand on a significant part-by-part basis, in addition to determining its overall inventory risk. We have incurred, and may in the future incur, charges to write-down inventory. See Note 6 - Inventory in the Notes to Consolidated Financial Statements for additional information related to inventory. Property, Plant, and Equipment Property, plant, and equipment are recorded at cost. Plant and equipment are depreciated on a straight-line basis over the estimated useful lives of the assets. We depreciate equipment over three five Valuation of Long-lived Assets Long-lived assets consist primarily of property, plant, and equipment, net. Since long-lived assets are subject to depreciation, we review these assets for impairment in accordance with the provisions of ASC 360, Property, Plant, and Equipment. We review long-lived assets for impairment whenever events or changes in circumstances indicate that its carrying amount may not be recoverable. Impairment testing of long-lived assets consists of determining whether the carrying amount of the long-lived asset (asset group) is recoverable, in other words, whether the sum of the future undiscounted cash flows expected to result from the use and eventual disposition of the asset (asset group) exceeds its carrying amount. The determination of the existence of impairment involves judgments that are subjective in nature and may require the use of estimates in forecasting future results and cash flows related to an asset or group of assets. In making this determination, we use certain assumptions, including estimates of future cash flows expected to be generated by these assets, which are based on additional assumptions such as asset utilization, the length of service that assets will be used in operations, and estimated salvage values. Asset Retirement and Environmental Obligations Pursuant to ASC 410, Asset Retirement and Environmental Obligations , an ARO is recorded when there is a legal obligation associated with the retirement of a tangible long-lived asset and the fair value of the liability can reasonably be estimated. Upon initial recognition of an ARO, a company increases the carrying amount of the long-lived asset by the same amount as the liability. Over time, the liabilities are accreted for the change in their present value through charges to operations costs. The initial capitalized costs are depleted over the useful lives of the related assets through charges to depreciation, and/or amortization. If the fair value of the estimated ARO changes, an adjustment is recorded to both the ARO and the asset retirement cost. Revisions in estimated liabilities can result from revisions of estimated inflation rates, escalating retirement costs, and changes in the estimated timing of settling ARO liabilities. Fair Value of Financial Instruments We determine the fair value of financial instruments in accordance with ASC 820, Fair Value Measurements and Disclosures. ASC Topic 820 (“ASC 820”), Fair Value Measurements, establishes a valuation hierarchy for disclosure of the inputs to valuation techniques used to measure fair value. This standard describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value: • Level 1 inputs are unadjusted quoted prices in active markets for identical assets or liabilities. • Level 2 inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the assets or liabilities, either directly or indirectly, through market corroboration, for substantially the full term of the financial instrument. • Level 3 inputs are unobservable inputs based on assumptions used to measure assets or liabilities at fair value. Classification of an asset or liability within this hierarchy is determined based on the lowest level input that is significant to the fair value measurement. Valuation techniques used to measure fair value under ASC 820 must maximize the use of observable inputs and minimize the use of unobservable inputs. Cash and cash equivalents consists primarily of bank deposits or highly liquid short-term investments with a maturity of three months or less at the time of purchase. Restricted cash represents temporarily restricted deposits held as compensating balances against short-term borrowing arrangements. Cash, cash equivalents and restricted cash are based on Level 1 measurements. The carrying amounts of cash and cash equivalents, restricted cash, accounts receivable, other current assets, and accounts payable approximate fair value because of the short maturity of these instruments. Revenue Recognition To determine the proper revenue recognition, we perform the following five steps: (a) identify the contract(s) with a customer; (b) identify the performance obligations in the contract; (c) determine the transaction price; (d) allocate the transaction price to the performance obligations in the contract; and (e) recognize revenue when (or as) we satisfy a performance obligation. We only apply the five-step model to contracts when it is probable that we will collect the consideration we are entitled to in exchange for the goods or services we transfer to the customer. The vast majority of revenues are from product sales to customers, pursuant to purchase orders with short lead times. Revenues from product sales are recognized when the customer obtains control of our product, which occurs at a point in time. The Company has elected to account for shipping and handling activities as a fulfillment cost as permitted by the standard. When we perform shipping and handling activities after the transfer of control to the customer (e.g. when control transfers prior to delivery), they are considered fulfillment activities, and accordingly, the costs are accrued when the related revenue is recognized. We expense incremental costs of obtaining a contract as and when incurred if the expected amortization period of the asset that we would have recognized is one year or less. In certain instances, inventory is maintained by customers at consigned locations. Revenues from consigned sales are recognized when the customer obtains control of our product, which occurs at a point in time. This is typically when the customer pulls product for use. We use a number of wholesale distributors around the world and recognize revenue when the wholesale distributor obtains control of our product, which occurs at a point in time, typically upon shipment. Wholesale distributors are contractually obligated to pay us on standard commercial terms, consistent with our end-use customers. We do not sell to wholesale distributors on consignment and do not give wholesale distributors a right of return. In certain instances, prior to customers accepting product that is manufactured at one of our CMs, these customers require that they first qualify the product and manufacturing processes at our CM (e.g. customer acceptance clause). The customers’ qualification process determines whether the product manufactured at our CM achieves their quality, performance, and reliability standards. After a customer completes the initial qualification process, we receive approval to ship qualified product to that customer. Revenues are recognized when the customer obtains control of the qualified product, which occurs at a point in time, typically upon shipment. To a lesser extent, we enter into other types of contracts including non-recurring engineering contracts. We recognize revenue for these arrangements over time or at a point in time depending on our evaluation of when the customer obtains control of the promised goods or services. For contracts that include multiple performance obligations, we allocate revenue to each performance obligation based on estimates of the relative standalone selling price that we would charge the customer for each promised product or service. Revenue from products and services transferred to customers over time accounted for 1%, 5%, and 4% of the Company’s revenue for the years ended September 30, 2021, 2020, and 2019, respectively. Receivables, Net Receivables, net, include amounts billed and currently due from customers. The amounts due are stated at their net estimated realizable value. Payments are generally due within 90 days or less of invoicing and do not include a significant financing component. We maintain an allowance for credit loss to provide for the estimated amount of receivables that will not be collected. The allowance is based upon an assessment of customer creditworthiness, historical payment experience, the age of outstanding receivables and collateral to the extent applicable. A contract asset is recognized when the Company has recognized revenue, but not issued an invoice for payment. Contract assets are classified as current assets and transferred to receivables when the entitlement to payment becomes unconditional. The Company’s contract assets are generally converted to trade account receivables within 90 days, at which time the Company is entitled to payment of the fixed price upon delivery of the finished product subject to customer payment terms. Remaining Performance Obligations Remaining performance obligations represent the transaction price of firm orders for long-term contracts which control has not transferred to the customer. As of September 30, 2021, the aggregate amount of the transaction price allocated to remaining performance obligations was $1.2 million. The Company expects to recognize revenue on approximately 100% of the remaining performance obligations over the next 12 months. Product Warranty Reserves We provide customers with warranty claims for certain products and warranty-related services are not considered a separate performance obligation. Pursuant to ASC 450, Contingencies , we make estimates of product warranty expense using historical experience rates and accrue estimated warranty expense as a cost of revenue. We estimate the costs of warranty obligations based on historical experience of known product failure rates and anticipated rates of warranty claims, use of materials to repair or replace defective products, and service delivery costs incurred in correcting the product issues. In addition, from time to time, specific warranty accruals may be made if unforeseen technical problems arise. Disaggregation of Revenue Revenue is classified within the Company’s segments. For additional information on the disaggregated revenues by geographical region and major product category, see Note 13 – Segment Data and Revenue Information in the Notes to Consolidated Financial Statements. Leases The Company adopted the new lease standard as of October 1, 2019 under the modified retrospective approach. Therefore, the consolidated financial statements for the year ended September 30, 2019 have not been adjusted and continued to be reported under previous U.S. GAAP guidance. Under the new lease standard, the Company determines if an arrangement is a lease at its inception. Right of use (ROU) assets and operating lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. The Company uses its estimated incremental borrowing rate in determining the present value of lease payments considering the term of the lease, which is derived from information available at the lease commencement date. The lease term includes renewal options when it is reasonably certain that the option will be exercised,

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recent Accounting Standards or Updates Not Yet Effective In December 2019, the FASB issued Accounting Standards Update ("ASU") 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which simplifies the accounting for income taxes by removing various exceptions, such as the exception to the incremental approach for intra-period tax allocation when there is a loss from continuing operations and income or a gain from other items. The amendments in this update also simplify the accounting for income taxes related to income-based franchise taxes and require that an entity reflect enacted tax laws or rates in the annual effective tax rate computation in the interim period that includes the enactment date. The new standard is effective for annual periods beginning after December 15, 2020, including interim periods within those annual periods. This accounting standard is effective in the first quarter of the Company's fiscal year ended September 30, 2022. The Company does not expect the adoption of this new guidance to have a material impact on the condensed consolidated financial statements. Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which changes the way entities measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net earnings. The new standard was effective for our fiscal year beginning October 1, 2020. The adoption of this standard did not have a material impact on the condensed consolidated financial statements.

Cash, Cash Equivalents, and Res

Cash, Cash Equivalents, and Restricted Cash	12 Months Ended
	Sep. 30, 2021
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same amounts shown in the consolidated statements of cash flows: As of September 30, (in thousands) 2021 2020 2019 Cash $ 16,547 $ 11,325 $ 4,338 Cash equivalents 55,074 19,065 17,236 Restricted cash 61 148 403 Total cash, cash equivalents and restricted cash $ 71,682 $ 30,538 $ 21,977

Accounts Receivable

Accounts Receivable	12 Months Ended
	Sep. 30, 2021
Receivables [Abstract]
Accounts Receivable	Accounts Receivable The components of accounts receivable consisted of the following: As of September 30, (in thousands) 2021 2020 Accounts receivable, gross $ 32,109 $ 25,551 Allowance for credit loss (260) (227) Accounts receivable, net $ 31,849 $ 25,324 The following table summarizes changes in the allowance for credit loss: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Balance at beginning of period $ 227 $ 148 $ 548 Provision adjustment - expense, net of recoveries 90 188 62 Write-offs and other deductions (57) (109) (462) Balance at end of period $ 260 $ 227 $ 148

Inventory

Inventory	12 Months Ended
	Sep. 30, 2021
Inventory Disclosure [Abstract]
Inventory	Inventory The components of inventory consisted of the following: As of September 30, (in thousands) 2021 2020 Raw materials $ 16,146 $ 13,354 Work in-process 11,410 8,381 Finished goods 4,753 3,790 Inventory balance at end of period $ 32,309 $ 25,525

Property, Plant, and Equipment,

Property, Plant, and Equipment, net	12 Months Ended
	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Property, Plant, and Equipment, net	Property, Plant, and Equipment, net The components of property, plant, and equipment, net consisted of the following: As of September 30, (in thousands) 2021 2020 Equipment $ 37,985 $ 35,218 Furniture and fixtures 1,125 1,125 Computer hardware and software 3,575 3,473 Leasehold improvements 6,663 3,169 Construction in progress 9,247 10,301 Property, plant, and equipment, gross $ 58,595 $ 53,286 Accumulated depreciation (36,051) (32,234) Property, plant, and equipment, net $ 22,544 $ 21,052 Depreciation expense totaled $4.0 million, $5.5 million and $7.1 million during the fiscal years ended September 30, 2021, 2020 and 2019, respectively. During the fiscal year ended September 30, 2021 and 2020 the Company sold certain equipment and recognized a (loss) gain on sale of assets of $(0.5) million and $2.3 million, respectively. In addition, in the fiscal year ended September 30, 2020, the Company entered into agreements to sell additional equipment and these assets were reclassified to assets held for sale. The balance as of September 30, 2021 and 2020 was $1.2 million and $1.6 million, respectively. In February 2020, SDI sold its property located in Concord, California (the "Concord Real Property") to Eagle Rock Holdings, LP ("Eagle Rock"), an affiliate of Parkview Management Group, Inc., for a total purchase price of $13.2 million. The Company received net proceeds of $12.8 million after reducing for transaction commissions and expenses incurred in connection with the sale. The Company recorded a gain on the sale of assets of approximately $0.3 million in the fiscal year ended September 30, 2020 related to this transaction. At the consummation of the sale of the Concord Real Property, SDI entered into a Single-Tenant Triple Net Lease (the “Concord Lease Agreement”) pursuant to which SDI leased back from Eagle Rock the Concord Real Property for a term commencing in February 2020 and ending February 2035, unless earlier terminated or extended in accordance with the terms of the Lease Agreement. As a result of the Concord Lease Agreement, the Company recorded net operating lease ROU assets and operating lease liabilities of $10.8 million during the fiscal year ended September 30, 2020. Geographical Concentrations Long-lived assets consist of land, building, and property, plant, and equipment. As of September 30, 2021 and 2020, approximately 96% and 97%, respectively, of long-lived assets were located in the United States. The remaining long-lived assets are primarily located in China.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Sep. 30, 2021
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities The components of accrued expenses and other current liabilities consisted of the following: As of September 30, (in thousands) 2021 2020 Compensation $ 7,192 $ 6,916 Warranty 1,125 803 Legal expenses and other professional fees 152 211 Contract liabilities 364 502 Income and other taxes 104 1,265 Severance and restructuring accruals — 17 Other 999 1,863 Accrued expenses and other current liabilities $ 9,936 $ 11,577 Severance and restructuring-related accruals specifically relate to the reductions in force. Expense related to severance and restructuring accruals is included in SG&A expense on the consolidated statements of operations and comprehensive income (loss). In an effort to better align current and future business operations related to CATV product lines, in August 2019 the Company reduced its workforce and recorded $0.5 million in severance expense in the fiscal year ended September 30, 2019. In January 2020, we further reduced our workforce and recorded $0.6 million in severance expense in the fiscal year ended September 30, 2020. There was $0.1 million in severance expense recorded in the fiscal year ended September 30, 2021. As of September 30, 2021 and 2020 there was $0 and $17.0 thousand accrued. The following table summarizes the changes in product warranty accrual accounts: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Balance at beginning of period $ 803 $ 654 $ 642 Provision for product warranty expense 505 626 186 Warranty liability assumed in acquisition liability — — 80 Adjustments and utilization of warranty accrual (183) (477) (254) Balance at end of period $ 1,125 $ 803 $ 654

Credit Facility and Debt

Credit Facility and Debt	12 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Credit Facility and Debt	Credit Facility and Debt Credit Facility On November 11, 2010, we entered into a Credit and Security Agreement (as amended to date, the “Credit Facility”) with Wells Fargo Bank, N.A. (“Wells Fargo”). The Credit Facility is secured by the Company’s assets and is subject to a borrowing base formula based on the Company’s eligible accounts receivable, inventory, and machinery and equipment accounts. The Credit Facility matures in February 2022 and currently provides us with a revolving credit line of up to $15.0 million at an interest rate equal to LIBOR plus 1.75%, subject to a borrowing base formula, that can be used for working capital requirements, letters of credit, acquisitions, and other general corporate purpose subject to a requirement, for certain specific uses, that the Company have liquidity of at least $25.0 million after such use. The Credit Facility requires us to maintain (a) liquidity of at least $10.0 million and (b) excess availability of at least $1.0 million. As of September 30, 2021, there were no amounts outstanding under this Credit Facility and the Company was in compliance with all financial covenants. Also, as of September 30, 2021, the Credit Facility had approximately $0.5 million reserved for one outstanding stand-by letter of credit and approximately $13.4 million available for borrowing. Debt On May 3, 2020, the Company entered into a Paycheck Protection Program Promissory Note and Agreement (the “PPP Loan Agreement”) with Wells Fargo under the Paycheck Protection Program established under the Coronavirus Aid, Relief and Economic Security Act and administered by the U.S. Small Business Administration (the "SBA") to receive loan proceeds of approximately $6.5 million, which the Company received on May 6, 2020. During 2021 the Company received a notification from Wells Fargo that the SBA approved the Company’s PPP Loan forgiveness application for the entire PPP Loan balance of approximately $6.5 million, including all accrued interest thereon, and that the remaining PPP Loan balance is zero. The forgiveness of the PPP Loan was recognized during the Company’s fiscal

Income and Other Taxes

Income and Other Taxes	12 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income and Other Taxes	Income and Other Taxes The Company’s income (loss) from operations before income taxes consisted of the following: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Domestic $ 25,744 $ (7,159) $ (35,100) Foreign 471 219 (830) Loss before income taxes $ 26,215 $ (6,940) $ (35,930) The Company’s income tax expense consisted of the following: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Federal: Current $ — $ 30 $ — Deferred — (43) — — (13) — State: Current 990 98 54 Deferred — (25) — 990 73 54 Foreign: Current (418) — — Deferred — — — (418) — — Total income tax expense $ 572 $ 60 $ 54 A reconciliation of the provision for income taxes, with the amount computed by applying the statutory U.S. federal and state income tax rates to continuing operations income before provision for income taxes is as follows: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Income tax expense (benefit) computed at U.S. federal statutory rate $ 5,506 $ (1,457) $ (7,540) State tax expense (benefit), net of U.S. federal effect 990 (156) (906) Foreign tax rate differential 24 13 (28) Effect due to change in tax rate — (137) (183) Shortfall from stock based compensation (122) 432 248 Other 103 94 223 Federal benefit on PPP loan forgiveness (1,363) — — Change in uncertain tax positions (419) — — State net operating loss carryforward adjustment 454 533 139 Change in valuation allowance (4,601) 738 8,101 Income tax expense $ 572 $ 60 $ 54 Effective tax rate 2.2 % 0.9 % 0.2 % Significant components of deferred tax assets are as follows: As of September 30, (in thousands) 2021 2020 Federal net operating loss carryforwards $ 96,289 $ 100,363 Foreign net operating loss carryforwards 1,372 1,680 Income tax credit carryforwards 2,510 2,671 Inventory reserves 2,229 2,320 Accounts receivable reserves 62 55 Accrued warranty reserve 269 193 State net operating loss carryforwards 6,356 5,970 Stock compensation 979 806 Deferred compensation 476 443 Fixed assets and intangibles (497) (348) ROU lease liability 3,289 3,529 ROU lease assets (3,195) (3,467) Other 1,372 1,322 Total deferred tax assets 111,511 115,537 Valuation allowance (111,511) (115,537) Net deferred tax liabilities $ — $ — For the fiscal years ended September 30, 2021, 2020 and 2019, the Company recorded income tax expense of approximately $0.6 million, $0.1 million and $0.1 million, respectively. Income tax expense for the fiscal year ended September 30, 2021 is comprised primarily of California state income tax due to temporary suspension of net operating loss credits and other state minimum tax expense, partially offset by the release of a reserve on uncertain tax benefits due to statutory limitation expiration. Income tax expense for the fiscal year ended September 30, 2020 is comprised primarily of state minimum tax expense partially offset by the reversal of a deferred tax liability related to the Concord Real Property. Income tax expense for the fiscal year ended September 30, 2019 is primarily comprised of state minimum tax expense. For the fiscal years ended September 30, 2021, 2020 and 2019, the effective tax rate on operations was 2.2%, 0.9% and 0.2%, respectively. The higher tax rate for the fiscal year ended September 30, 2021 is primarily due to the higher California state income tax due to temporary suspension of net operating loss credits. The lower tax rate for the fiscal year ended September 30, 2020 was primarily due to the operating loss and state minimum tax expense. The lower tax rate for the fiscal year ended September 30, 2019 was primarily due to the effect of the Tax Cuts and Jobs Act of 2017, which resulted in a credit to the Company on future tax payments for past AMT amounts paid and the current period operating loss. The Company uses some estimates to forecast permanent differences between book and tax accounting. We have not provided for income taxes on non-U.S. subsidiaries’ undistributed earnings as of September 30, 2021 because we plan to indefinitely reinvest the unremitted earnings of the non-U.S. subsidiaries and all of the non-U.S. subsidiaries historically have negative earnings and profits. All deferred tax assets have a full valuation allowance at September 30, 2021. On a quarterly basis, the Company evaluates the positive and negative evidence to assess whether the more likely than not criteria, has been satisfied in determining whether there will be further adjustments to the valuation allowance. During the fiscal years ended September 30, 2021, the Company released the ASC 740-10 reserve on uncertain tax benefits due to statutory limitation expiration. During the fiscal year ended September 30, 2020, there were no material increases or decreases in unrecognized tax benefits. As of September 30, 2021, the Company had net operating loss carryforwards for U.S. federal income tax purposes of approximately $458.5 million which begin to expire in 2022. As of September 30, 2021, the Company had foreign net operating loss carryforwards of $5.5 million which begin to expire in 2022 as well as state net operating loss carryforwards of approximately $72.8 million which begin to expire in 2022. As of September 30, 2021, the Company also had tax credits (primarily foreign income and U.S. research and development tax credits) of approximately $2.5 million. The research credits begin to expire in 2022. Utilization of net operating loss and tax credit carryforwards are subject to a substantial annual limitation due to the ownership change limitations set forth in Section 382 of the Code and similar state provisions. The Company prepared an Internal Revenue Code 382 analysis to determine the annual limitations on the Company’s consolidated net operating loss carryforwards. As a result of the $458.5 million of U.S. net operating loss carryforwards, approximately $230.2 million is subject to an annual limitation and $228.3 million of the net operating losses are not subject to an annual limitation. Such annual limitations could result in the expiration of the net operating loss and tax credit carryforwards before utilization. A reconciliation of the beginning and ending amount of unrecognized gross tax benefits is as follows: (in thousands) Amount Balance as of September 30, 2019 $ 419 Adjustments based on tax positions related to the current year — Adjustments based on tax positions of prior years — Balance as of September 30, 2020 419 Adjustments based on tax positions related to the current year — Adjustments based on tax positions of prior years (419) Balance as of September 30, 2021 $ — As of September 30, 2021 and 2020, we had approximately $0 million and $0.6 million, respectively, of interest and penalties accrued as tax liabilities on the balance sheet. As we released the entire unrecognized tax benefits, as well as the associated interest and penalties as of September 30, 2021, there is no uncertain tax positions that will be paid or settled within the next 12 months . Interest that is accrued on tax liabilities is recorded within interest expense on the consolidated statements of operations.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Leases We lease certain facilities and equipment under non-cancelable operating leases. Operating lease amounts exclude property taxes, insurance, and maintenance expenses on leased properties. As of September 30, 2021, our operating leases had remaining lease terms of 0.6 years to 13.4 years, some of which included options to extend 5 additional years. During the fiscal years ended September 30, 2021 and 2020, the Company recorded $2.2 million and $1.8 million of operating lease expense, respectively. The Company's finance leases and short term leases are immaterial. Maturities of operating lease liabilities as of September 30, 2021 were as follows: (in thousands) Amount 2022 $ 1,955 2023 1,856 2024 1,686 2025 1,730 2026 1,775 Thereafter 10,592 Total lease payments $ 19,594 Less imputed interest (5,712) Total $ 13,882 Weighted-average remaining lease term and discount rate related to operating leases are as follows: As of September 30, 2021 2020 Weighted average remaining lease term (years) 11.9 14.4 Weighted average discount rate 6.1 % 6.1 % Supplemental cash information and non-cash activities related to operating leases are as follows: As of September 30, (in thousands) 2021 2020 Operating cash outflows from operating leases $ 1,975 $ 1,592 Right-of-use assets obtained in exchange for operating lease liabilities $ 10,358 $ 10,791 Asset Retirement Obligations The Company’s ARO consists of legal requirements to decommission assets, restoration of the existing leased facilities to their original state, and certain environmental work to be performed due to the presence of a manufacturing fabrication operation. ARO includes assumptions related to renewal option periods for those facilities where we expect to extend lease terms. The Company recognizes its estimate of the fair value of its ARO in the period incurred in long-term liabilities. The fair value of the ARO is also capitalized as property, plant and equipment. In connection with the Company's lease agreements, we have recorded an ARO liability of $2.0 million and $2.0 million at September 30, 2021 and September 30, 2020, respectively. The fair value of ARO was estimated by discounting projected cash flows over the estimated life of the related assets using credit adjusted risk-free rates which ranged from 0.06% to 1.73%. Accretion expense of $47.6 thousand, $31.9 thousand and $54.2 thousand was recorded during the fiscal years ended September 30, 2021, 2020 and 2019, respectively. The following table summarizes ARO activity: (in thousands) Amount Balance at September 30, 2020 $ 2,022 Accretion expense 48 Revision in estimated cash flows (21) Balance at September 30, 2021 $ 2,049 Indemnifications We have agreed to indemnify certain customers against claims of infringement of intellectual property rights of others in sales contracts with these customers. Historically, we have not paid any claims under these customer indemnification obligations. We enter into indemnification agreements with each director and executive officer pursuant to which we agree to indemnify them for certain potential expenses and liabilities arising from their status as a director or executive officer of the Company. We maintain director and officer insurance, which may cover certain liabilities arising from the obligation to indemnify directors and executive officers in certain circumstances. It is not possible to determine the aggregate maximum potential loss under these indemnification agreements due to the limited history of prior indemnification claims and the unique facts and circumstances involved in each particular claim. Legal Proceedings We are subject to various legal proceedings, claims, and litigation, either asserted or unasserted, that arise in the ordinary course of business. Except as described below, the outcome of these matters is currently not determinable and we are unable to estimate a range of loss, should a loss occur, from these proceedings. The ultimate outcome of legal proceedings involves judgments, estimates and inherent uncertainties and the results of these matters cannot be predicted with certainty. Professional legal fees are expensed when incurred. We accrue for contingent losses when such losses are probable and reasonably estimable. In the event that estimates or assumptions prove to differ from actual results, adjustments are made in subsequent periods to reflect more current information. Should we fail to prevail in any legal matter or should several legal matters be resolved against the Company in the same reporting period, then the financial results of that particular reporting period could be materially affected. Intellectual Property Lawsuits We protect our proprietary technology by applying for patents where appropriate and, in other cases, by preserving the technology, related know-how and information as trade secrets. The success and competitive position of our product lines are impacted by the ability to obtain intellectual property protection for research and development efforts. We have, from time to time, exchanged correspondence with third parties regarding the assertion of patent or other intellectual property rights in connection with certain of our products and processes. Phoenix Legal Proceedings On June 12, 2018, Phoenix commenced an arbitration against EMCORE with the AAA in New York. On August 31, 2018, Phoenix filed a First Amended Demand for Arbitration, asserting the following claims: breach of contract, breach of the covenant of good faith and fair dealing, misappropriation of trade secrets (under the Defend Trade Secrets Act, 18 U.S.C. § 1836, and New York law), conversion, unjust enrichment, correction of inventorship relating to U.S. Patent No. 8,773,665, and declaratory relief, relating to EMCORE’s termination of certain agreements entered into between EMCORE and Phoenix related to the purported license of certain intellectual property related to FOG technology and disputed royalty payments related thereto. On September 14, 2018, EMCORE filed an Answering Statement and Counterclaim, denying all of Phoenix’s claims and asserting counterclaims for breach of the implied covenant of good faith and fair dealing and declaratory relief. On June 21, 2019, an interim award (the “Interim Award”) was issued in connection with all claims in the AAA proceeding other than the claims related to correction of inventorship and declaratory relief relating to U.S. Patent No. 8,773,665 (the “Patent Claims”). While Phoenix ultimately sought $21.2 million in total damages, plus attorneys’ fees and costs, in the Interim Award, the arbitrator found in the Interim Award that (a) Phoenix’s claim for breach of the covenant of good faith and fair dealing was denied; (b) Phoenix’s claim for breach of the agreements entered with EMCORE for failure to provide funding for non-recurring engineering was denied; (c) Phoenix’s claim for unjust enrichment was denied; (d) Phoenix’s claim for conversion was granted, but damages for that claim duplicate the damages on the breach of contract and misappropriation of trade secret claims described below and no incremental damages were awarded based on the granting of this claim; and (e) EMCORE’s request for a declaration that, as between EMCORE and Phoenix, EMCORE owns its proprietary IOC and transceiver was granted. The arbitrator also found in the Interim Award that (a) EMCORE breached certain license agreements entered into with Phoenix by failing to make royalty payments due and failing to provide required accounting, (b) Phoenix and its members are no longer subject to prior exclusivity restrictions; (c) EMCORE’s claim for breach of the covenant of good faith and fair dealing was denied; and (d) the proceedings for the Patent Claims and EMCORE’s counterclaim with respect thereto would be established by a future proceeding. Further, out of the original 97 trade secret subpart claims by Phoenix, the arbitrator found in the Interim Award that EMCORE had misappropriated a total of five trade secret subparts (the “Deemed Trade Secrets”), and found that at least one Deemed Trade Secret was being used in seven EMCORE products (the “EMCORE Products”). The arbitrator found that as a result of the foregoing, royalties of 7.5% of the sale price are owed, to the extent not previously paid, on (a) sales through July 16, 2018 on all FOGs sold by EMCORE, and (b) sales from July 16, 2018 through May 31, 2019 of the EMCORE Products whether standalone or incorporated into a larger product, in each case together with interest at the New York statutory rate of 9% simple interest. In addition, the arbitrator found in the Interim Award that Phoenix was the prevailing party, and Phoenix was awarded attorneys’ fees and costs in the amount of approximately $3.7 million, which amount was reduced 10% from Phoenix’s attorneys’ fees request. In the Interim Award, the arbitrator further determined that EMCORE shall pay Phoenix a royalty of 7.5% of the sale price on (a) future customer payments for certain EMCORE product contracts previously entered into and (b) customer payments for future sales of any product using any Deemed Trade Secret, in each case payable in a single lump sum within one month of completion of the calendar quarter in which payment has been received from the customer, and shall concurrently submit to Phoenix a written report that sets forth the calculation of the amount of the royalty payment in a form similar to previous royalty reports, provided that following the first $1 million of royalty payments on the EMP-1 product only, inclusive of payments made to date, EMCORE will pay to Phoenix a royalty of 2.25% of the sale price (net of any warranty work, returns, rebates, discounts or credits). EMCORE is required to continue to make royalty payments in this manner until such time as it has in good faith determined, and can so document, that it has completely ceased use of the Deemed Trade Secrets, and at such time, EMCORE shall provide Phoenix written notice of same. On October 1, 2019, the arbitrator issued a Modified Partial Final Award, which incorporated by reference the terms of the Interim Award and ordered and awarded, among other items, (a) an award to Phoenix of attorneys’ fees and costs in the amount of approximately $3.8 million, (b) an award to Phoenix of $1.0 million in damages owing for unpaid royalties through June 30, 2019, of which $0.6 million remained to be paid as of the issuance of the Modified Partial Final Award, (c) an award to Phoenix of $0.1 million in pre-judgment interest, calculated at the New York statutory rate of 9% simple interest, and (d) an order that EMCORE make the payments in the foregoing items (a), (b) and (c) on or before October 14, 2019. On October 10, 2019, EMCORE made the foregoing payments to Phoenix in an aggregate amount equal to approximately $4.5 million. This amount was accrued as of September 30, 2019 and paid during the fiscal year ended September 30, 2020. During the fiscal year ended September 30, 2019, we recorded the award and settlement to Phoenix of attorneys’ fees and costs in the amount of approximately $3.8 million, and legal expenses of approximately $5.7 million within selling, general and administrative expense on the consolidated statement of operations and comprehensive (loss) income. The Patent Claims were not determined in the Interim Award or the Modified Partial Final Award. In December 2019, EMCORE and Phoenix entered into a settlement agreement with respect to the Patent Claims pursuant to which EMCORE (a) granted Phoenix a fully paid, perpetual nonexclusive license to the disputed patent and (b) agreed to pay Phoenix a total of $0.4 million, of which $0.2 million was paid in January 2020, $0.1 million was paid in April 2020 and $0.1 million was paid in July 2020. During the fiscal year ended September 30, 2020, the Company recorded the settlement of the Patent Claims in the amount of approximately $0.4 million within selling, general and administrative expense on the consolidated statement of operations and comprehensive loss. On June 21, 2018, Phoenix commenced a special proceeding against EMCORE in the New York Supreme Court, Commercial Division. As part of the special proceeding, Phoenix filed an application for a preliminary injunction in aid of arbitration pursuant to CLPR 7502(c), in connection with the AAA arbitration proceeding in New York. The application resulted in a so-ordered stipulated injunction between EMCORE and Phoenix, which was entered in August 2018. In January 2020, the court granted a motion to confirm the Modified Partial Final Award, vacated the so-ordered stipulated injunction entered in August 2018, and disposed of the special proceeding. Resilience Litigation In February 2021, Resilience Capital (“Resilience”) filed a complaint against us with the Delaware Chancery Court containing claims arising from the February 2020 sale of SDI’s real property (the “Concord Property Sale”) located in Concord, California (the “Concord Real Property”) to Eagle Rock and that certain Single-Tenant Triple Net Lease, dated as of February 10, 2020, entered into by and between SDI and Eagle Rock, pursuant to which SDI leased from Eagle Rock the Concord Real Property for a 15 year term. The Resilience complaint seeks, among other items, (a) a declaration that the Concord Property Sale included a non-cash component; (b) a decree requiring us and Resilience to follow the appraisal requirements set forth in that certain Purchase and Sale Agreement (the "SDI Purchase Agreement"), dated as of June 7, 2019, by and among the Company, The Resilience Fund IV, L.P., The Resilience Fund IV-A, L.P., Aerospace Newco Holdings, Inc. and Ember Acquisition Sub, Inc.; (c) recovery of Resilience’s costs and expenses; and (d) pre- and post-judgment interest. In April 2021, we filed with the Delaware Chancery Court our answer to the Resilience complaint and counterclaims against Resilience, in which we are seeking, among other items, (a) dismissal of the Resilience complaint and/or granting of judgment in favor of EMCORE with respect to the Resilience complaint, (b) entering final judgment against Resilience awarding damages to us for Resilience’s fraud and breaches of the SDI Purchase Agreement in an amount to be proven at trial and not less than $1,565,000, (c) a judicial determination of the respective rights and duties of us and Resilience under the SDI Purchase Agreement, (d) an award to us of costs and expenses and (e) pre- and post-judgment interest. We believe that the claims made by Resilience in its complaint are without merit and we intend to vigorously defend ourselves against them.

Equity

Equity	12 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Equity	Equity Equity Plans We provide long-term incentives to eligible officers, directors, and employees in the form of equity-based awards. We maintain three equity incentive compensation plans, collectively described below as “Equity Plans” including the 2010 Equity Incentive Plan ("2010 Plan"), the 2012 Equity Incentive Plan ("2012 Plan"), and the 2019 Equity Incentive Plan ("2019 Plan"). We issue new shares of common stock to satisfy awards issued under our Equity Plans. In March 2021, our shareholders approved the Amended and Restated EMCORE Corporation 2019 Equity Incentive Plan, which was adopted by the Company’s Board of Directors in December 2020 and increased the maximum number of shares of the Company’s common stock that may be issued or transferred pursuant to awards under the 2019 Equity Incentive Plan by an additional 2,138,000 shares. Stock Options Most stock options vest and become exercisable over four The following table summarizes stock option activity under the Equity Plans for the fiscal year ended September 30, 2021: Number of Weighted Weighted Aggregate Outstanding as of September 30, 2020 44,065 $ 5.14 Granted — — Exercised (15,025) 5.13 Forfeited — — Expired (9,171) 6.35 Outstanding as of September 30, 2021 19,869 $ 4.59 3.75 $ 57 Exercisable as of September 30, 2021 19,869 $ 4.59 3.75 $ 57 Vested and expected to vest as of September 30, 2021 19,869 $ 4.59 3.75 $ 57 ___________________________________________ (*) Intrinsic value for stock options represents the “in-the-money” portion or the positive variance between a stock option’s exercise price and the underlying stock price. For the fiscal year ended September 30, 2020, the intrinsic value of options exercised was $0. As of September 30, 2021, there was no unrecognized stock-based compensation expense related to non-vested stock options granted under the Equity Plans. Valuation Assumptions There were no stock option grants for the fiscal years ended September 30, 2021 and 2020. Time-Based Restricted Stock Time-based restricted stock units (“RSU”) and restricted stock awards (“RSA”) granted to employees under the 2010 Plan, 2012 Plan or 2019 Plan typically vest over 3 to 4 years and are subject to forfeiture if employment terminates prior to the vesting or lapse of the restrictions, as applicable. RSUs are not considered issued or outstanding common stock until they vest. RSAs are considered issued and outstanding on the grant date and are subject to forfeiture if specified vesting conditions are not satisfied. The following table summarizes the activity related to RSUs and RSAs subject to time-based vesting requirements for the fiscal year ended September 30, 2021: RSUs RSAs Number of Shares Weighted Number of Weighted Non-vested as of September 30, 2020 1,548,045 $ 3.41 8,154 $ 8.20 Granted 1,045,673 5.55 — — Vested (598,986) 3.43 (8,154) 8.20 Forfeited (189,878) 3.70 — — Non-vested as of September 30, 2021 1,804,854 $ 4.61 — $ — As of September 30, 2021, there was approximately $6.7 million of remaining unamortized stock-based compensation expense associated with RSUs, which will be expensed over a weighted average remaining service period of approximately 2.7 years. The 1.8 million outstanding non-vested and expected to vest RSUs have an aggregate intrinsic value of $13.5 million and a weighted average remaining contractual term of 2.7 years. For the fiscal years ended September 30, 2021, 2020, and 2019, the intrinsic value of RSUs vested was approximately $3.6 million, $1.3 million and $1.4 million, respectively. For the fiscal years ended September 30, 2020 and 2019, the weighted average grant date fair value of RSUs granted was $3.41 and $3.68 per share, respectively. For the fiscal year ended September 30, 2021, $27.3 thousand of RSAs vested. As of September 30, 2021, there was no remaining unamortized stock-based compensation expense associated with RSAs. Performance Stock Performance based restricted stock units (“PSU”) and performance based shares of restricted stock (“PRSA”) granted to employees under the 2012 Plan or 2019 Plan typically vest over 1 to 3 years and are subject to forfeiture in whole, if employment terminates, or in whole or in part, if specified vesting conditions are not satisfied, in each case prior to vesting. PSUs are not considered issued or outstanding common stock until they vest. PRSAs are considered issued and outstanding on the grant date and are subject to forfeiture if specified vesting conditions are not satisfied. PSUs and PRSAs that are granted to executive officers and key employees are provided as long-term incentive compensation that is based on relative total shareholder return, which measures performance against the Russell Microcap Index. The following table summarizes the activity related to PSUs for the fiscal year ended September 30, 2021: PSUs Number of Shares Weighted Average Grant Date Fair Value Non-vested as of September 30, 2020 868,500 $ 4.79 Granted 231,000 7.39 Vested (6,086) 7.91 Forfeited (126,414) 7.70 Non-vested as of September 30, 2021 967,000 $ 5.01 As of September 30, 2021, there was approximately $2.4 million of remaining unamortized stock-based compensation expense associated with PSUs, which will be expensed over a weighted average remaining service period of approximately 1.3 years. The 1.0 million outstanding non-vested and expected to vest PSUs have an aggregate intrinsic value of approximately $7.2 million and a weighted average remaining contractual term of 1.3 years. For the fiscal years ended September 30, 2021, 2020 and 2019, the intrinsic value of PSUs vested was $34.4 thousand, $0.0 million and $0.2 million, respectively. For the fiscal years ended September 30, 2020 and 2019, the weighted average grant date fair value of PSUs granted was $3.81 and $5.19 per share, respectively. As of September 30, 2020, there was no remaining unamortized stock-based compensation expense associated with PRSAs. Stock-based Compensation The following table set forth stock-based compensation expense by award type: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Employee stock options $ 2 $ 13 $ 25 RSUs and RSAs 2,093 1,755 1,495 PSUs and PRSAs 1,396 1,243 685 ESPP 307 214 180 Outside director equity awards and fees in common stock 382 291 221 Total stock-based compensation expense $ 4,180 $ 3,516 $ 2,606 The following table set forth stock-based compensation expense by expense type: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Cost of revenue $ 767 $ 692 $ 482 Selling, general, and administrative 2,590 2,155 1,478 Research and development 823 669 646 Total stock-based compensation expense $ 4,180 $ 3,516 $ 2,606 Stock-based compensation within SG&A expense was lower for the fiscal year ended September 30, 2019 due to the reversal of previously recognized expense associated with the forfeiture of unvested RSUs and PSUs of the former CFO. Capital Stock Authorized capital stock consists of 50 million shares of common stock, no par value, and 5,882,352 shares of preferred stock, $0.0001 par value. On February 16, 2021, the Company closed our offering of 6,655,093 shares of our common stock, which included the full exercise of the underwriters’ option to purchase 868,056 additional shares of common stock, at a price to the public of $5.40 per share, resulting in net proceeds to us from the offering, after deducting the underwriting discounts and commissions and other offering expenses, of approximately $33.1 million. The shares were sold by us pursuant to an underwriting agreement with Cowen and Company, LLC, dated as of February 10, 2021. As of September 30, 2021 and 2020, we had 43.9 million and 36.5 million shares of common stock issued and outstanding, respectively. There were no shares of preferred stock issued or outstanding as of September 30, 2021 and 2020. 401(k) Plan The Company has a savings plan that qualifies as a deferred salary arrangement under Section 401(k) of the Code. Under this savings plan, participating employees may defer a portion of their pretax earnings, up to the Internal Revenue Service annual contribution limit. Since June 2015, all employer contributions are made in cash. Our matching contribution in cash for each of the fiscal years ended September 30, 2021, 2020 and 2019 was approximately $1.1 million, $1.0 million, and $0.6 million, respectively. Earnings (Loss) per Share The following table sets forth the computation of basic and diluted earnings (loss) per share: For the Fiscal Year Ended September 30, (in thousands, except per share) 2021 2020 2019 Numerator Net income (loss) $ 25,643 $ (7,000) $ (35,984) Denominator Weighted average number of shares outstanding - basic 34,020 29,136 27,983 Effect of dilutive securities Stock options 7 — — PSUs, RSUs, and restricted stock 1,762 — — Weighted average number of shares outstanding - diluted 35,789 29,136 27,983 Earnings (loss) per share - basic $ 0.75 $ (0.24) $ (1.29) Earnings (loss) per share - diluted $ 0.72 $ (0.24) $ (1.29) Weighted average antidilutive options, unvested RSUs and RSAs, unvested PSUs and ESPP shares excluded from the computation 195 1,109 810 Basic EPS is computed by dividing net income (loss) for the period by the weighted-average number of common stock outstanding during the period. Diluted EPS is computed by dividing net income (loss) for the period by the weighted average number of common stock outstanding during the period, plus the dilutive effect of outstanding RSUs and RSAs, PSUs, stock options, and shares issuable under the Employee Stock Purchase Plan ("ESPP") as applicable pursuant to the treasury stock method. Certain of the Company's outstanding share-based awards, noted in the table above, were excluded because they were anti-dilutive, but they could become dilutive in the future. The dilutive stock options and unvested stock were excluded from the computation of diluted net loss per share for the fiscal years ended September 30, 2020 and 2019 due to the Company incurring a net loss for the period. ESPP Until September 2021, we maintained the ESPP, which provided employees an opportunity to purchase common stock through payroll deductions. The ESPP was a 6-month duration plan with new participation periods beginning on approximately February 25 and August 26 each year, with the purchase price set at 85% of the average high and low market price of common stock on either the first or last trading day of the participation period, whichever was lower, and annual contributions were limited to the lower of 10% of an employee’s compensation or $25.0 thousand. In September 2021, the Compensation Committee of our Board Directors approved the termination of the ESPP, effective immediately. Prior to termination of the ESPP, we issued new shares of common stock to satisfy the issuance of shares under this stock-based compensation plan. Common stock issued under the ESPP during the fiscal years ended September 30, 2021, 2020 and 2019 totaled approximately 192.0 thousand, 231.0 thousand and 197.0 thousand shares, respectively. As of September 30, 2021, the total amount of common stock issued under the ESPP totaled 3,395,090 shares and the total shares remaining available for issuance under the ESPP totaled 0. Future Issuances As of September 30, 2021, we had common stock reserved for the following future issuances: Number of Common Exercise of outstanding stock options 19,869 Unvested RSUs and RSAs 1,804,854 Unvested PSUs and PRSAs (at 200% maximum payout) 1,934,000 Issuance of stock-based awards under the Equity Plans 1,751,234 Purchases under the officer and director share purchase plan 88,741 Total reserved 5,598,698

Segment and Revenue Information

Segment and Revenue Information	12 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Segment and Revenue Information	Segment and Revenue Information Reportable Segments Reported below are the Company’s segments for which separate financial information is available and upon which operating results are evaluated by the chief operating decision maker, the Chief Executive Officer, to assess performance and to allocate resources. We do not allocate sales and marketing or general and administrative expenses, or interest expense and interest income to our segments, because management does not include the information in its measurement of the performance of the operating segments. Also, a measure of segment assets and liabilities has not been provided to the Company's chief operating decision maker and therefore is not shown below. Information on reportable segments utilized by the chief operating decision maker is as follows: (in thousands) For the Fiscal Year Ended September 30, 2021 2020 2019 Revenue Aerospace and Defense $ 50,838 $ 55,240 $ 33,086 Broadband 107,606 54,888 54,179 Total revenue $ 158,444 $ 110,128 $ 87,265 Segment income (loss) Aerospace and Defense gross profit $ 13,705 $ 16,729 $ 9,207 Aerospace and Defense research and development expense 14,616 17,469 10,448 Aerospace and Defense segment loss $ (911) $ (740) $ (1,241) Broadband gross profit $ 47,783 $ 18,853 $ 5,882 Broadband research and development expense 2,832 2,800 8,995 Broadband segment income (loss) $ 44,951 $ 16,053 $ (3,113) Consolidated segment income (loss) $ 44,040 $ 15,313 $ (4,354) Unallocated operating expense Selling, general, and administrative $ 24,544 $ 24,631 $ 32,080 Loss (gain) on sale of assets 515 (2,284) (302) Total unallocated operating expense $ 25,059 $ 22,347 $ 31,778 Operating income (loss) $ 18,981 $ (7,034) $ (36,132) Product Categories Revenue is also classified by major product category and is presented below: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Aerospace and Defense Navigation and Inertial Sensing $ 36,539 $ 38,983 $ 23,203 Defense Optoelectronics 14,299 16,257 9,883 Broadband CATV Lasers and Transmitters 95,255 44,457 41,150 Chip Devices 3,106 4,873 10,828 Other Optical Products 9,245 5,558 2,201 Total revenue $ 158,444 $ 110,128 $ 87,265 Geographical Concentration The following table sets forth revenue by geographic area based on customers’ billing address: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 United States and Canada $ 139,443 $ 91,205 $ 68,607 Asia 11,836 9,397 11,637 Europe 4,802 5,559 6,209 Other 2,363 3,967 812 Total revenue $ 158,444 $ 110,128 $ 87,265 Significant Customers Significant customers are defined as customers representing greater than 10% of consolidated revenue. Revenue from three, three and three significant customers represented an aggregate of 70%, 57% and 55% of consolidated revenue for the fiscal years ended September 30, 2021, 2020 and 2019, respectively. The percentage from significant customers increased driven by higher Broadband revenue. Significant portions of the Company’s sales are concentrated among a limited number of customers. The duration, severity, and future impact of the COVID-19 pandemic are highly uncertain and could result in significant disruptions to the business operations of the Company’s customers. If one or more of these significant customers significantly decreases their orders for the Company’s products, or if we are unable to deliver finished products to the customer in connection with such orders, the Company’s business could be materially and adversely affected.

Subsequent Events

Subsequent Events	12 Months Ended
	Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsOn November 1, 2021, we entered into an Amendment to Lease (the “New Alhambra Lease Amendment”) to that certain Standard Industrial/Commercial Single-Tenant Lease – Net, dated as of October 1, 2017, by and between the Company and CHESTNUT2015 LLC (the “Alhambra Lease”), as previously amended by that certain Amendment to Lease, dated as of March 31, 2019 (the “Original Alhambra Lease Amendment”). Pursuant to the terms of the New Alhambra Lease Amendment, we agreed to extend the term of the lease for our corporate headquarters, manufacturing and research and development facilities located in Alhambra, California (the “Leased Facilities”) through September 30, 2031, with a five-year Company option to extend beyond such expiration date. Under the terms of the New Alhambra Lease Amendment, base rent for the Leased Facilities will remain unchanged from the rates of $51,500 per month during the fiscal year ending September 30, 2022 and $53,500 per month during the fiscal year ending September 30, 2023, in each case as previously agreed in the Original Alhambra Lease Amendment, and we continue to be responsible for certain other monthly expenses related to the Leased Facilities, including taxes and utilities. Base rent for the fiscal year ending September 30, 2024 will be based on a mutually determined fair market value, subject to the appraisal process set forth in New Alhambra Lease Amendment, which amount shall be at least 2% greater than the monthly rent paid during the fiscal year ending September 30, 2023. Monthly base rent for the fiscal year ending September 30, 2025 and each fiscal year thereafter during the term of the lease shall increase from the monthly rent payable in the immediately preceding fiscal year in an amount equal to the percentage increase, from the immediately preceding fiscal year, in the most recently published Consumer Price Index for All Urban Consumers, Los Angeles-Long Beach-Anaheim area, published by the Bureau of Labor Statistics of the U.S. Department of Labor.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Principles of Consolidation and Going Concern Basis	Principles of Consolidation The consolidated financial statements have been prepared in accordance with U.S. GAAP and include the assets, liabilities, shareholders’ equity, and operating results of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The Company is not the primary beneficiary of, nor do we hold a significant variable interest in, any variable interest entity. Going Concern Basis The consolidated financial statements included herein have been prepared on a going concern basis, which contemplates continuity of operations and the realization of assets and the repayment of liabilities in the ordinary course of business. Management evaluated the significance of the Company’s recent operating losses and determined that the Company’s current cash on hand, operating plan, and sources of capital will be sufficient for the Company to continue as a going concern. The Company has taken a number of actions to continue to support its operations and meet its obligations, including headcount and cost reductions, monetization of certain fixed assets and real estate, and entering into financing activities. The Company believes that its existing liquidity will be sufficient to meet anticipated cash needs for at least the next 12 months from the issuance date of these financial statements.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities, as of the date of the financial statements, and the reported amounts of revenue and expenses during the reported period. Such estimates include accounts receivable; inventories; goodwill; long-lived assets; product warranty liabilities; legal contingencies; and income taxes. We develop estimates based on historical experience and on various assumptions about the future that are believed to be reasonable based on the best information available to us. Our reported financial position or results of operations may be materially different under changed conditions or when using different estimates and assumptions, particularly with respect to significant accounting policies. In the event that estimates or assumptions prove to differ from actual results, adjustments are made in subsequent periods to reflect more current information.
Concentration of Credit Risk	Concentration of Credit RiskFinancial instruments that may subject us to concentrations of credit risk consist primarily of accounts receivable. When necessary, we perform credit evaluations on customers’ financial condition and occasionally we request deposits in advance of shipping product to customers. These financial evaluations require significant judgment and are based on a variety of factors including, but not limited to, current economic trends, historical payment patterns, bad debt write-off experience, and financial review of the particular customer.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consists primarily of bank deposits and highly liquid short-term investments with a maturity of three months or less at the time of purchase.
Restricted Cash	Restricted Cash Restricted cash represents recently deposited cash that is temporarily restricted by our bank in accordance with the terms of the outstanding credit facility.
Accounts Receivable	Accounts Receivable We regularly evaluate the collectability of accounts receivable and maintain allowances for doubtful accounts for estimated losses resulting from the inability of customers to meet their financial obligations to us. The allowance is based on the age of receivables and a specific identification of receivables considered at risk of collection. We classify charges associated with the allowance for doubtful accounts as selling, general, and administrative expense.
Inventory	Inventory Inventory is stated at the lower of cost or net realizable value (first-in, first-out). Inventory that is expected to be used within the next 12 months is classified as current inventory. We write-down inventory once it has been determined that conditions exist that may not allow the inventory to be sold for its intended purpose or the inventory is determined to be excess or obsolete based on assumptions about future demand and market conditions. The charge related to inventory write-downs is recorded as cost of revenue. We evaluate inventory levels at least quarterly against an estimate of future demand on a significant part-by-part basis, in addition to determining its overall inventory risk. We have incurred, and may in the future incur, charges to write-down inventory. See Note 6 - Inventory in the Notes to Consolidated Financial Statements for additional information related to inventory.
Property, Plant, and Equipment	Property, Plant, and Equipment Property, plant, and equipment are recorded at cost. Plant and equipment are depreciated on a straight-line basis over the estimated useful lives of the assets. We depreciate equipment over three five
Valuation of Long-lived Assets	Valuation of Long-lived Assets Long-lived assets consist primarily of property, plant, and equipment, net. Since long-lived assets are subject to depreciation, we review these assets for impairment in accordance with the provisions of ASC 360, Property, Plant, and Equipment. We review long-lived assets for impairment whenever events or changes in circumstances indicate that its carrying amount may not be recoverable. Impairment testing of long-lived assets consists of determining whether the carrying amount of the long-lived asset (asset group) is recoverable, in other words, whether the sum of the future undiscounted cash flows expected to result from the use and eventual disposition of the asset (asset group) exceeds its carrying amount. The determination of the existence of impairment involves judgments that are subjective in nature and may require the use of estimates in forecasting future results and cash flows related to an asset or group of assets. In making this determination, we use certain assumptions, including estimates of future cash flows expected to be generated by these assets, which are based on additional assumptions such as asset utilization, the length of service that assets will be used in operations, and estimated salvage values.
Asset Retirement and Environmental Obligations	Asset Retirement and Environmental Obligations Pursuant to ASC 410, Asset Retirement and Environmental Obligations , an ARO is recorded when there is a legal obligation associated with the retirement of a tangible long-lived asset and the fair value of the liability can reasonably be estimated. Upon initial recognition of an ARO, a company increases the carrying amount of the long-lived asset by the same amount as the liability. Over time, the liabilities are accreted for the change in their present value through charges to operations costs. The initial capitalized costs are depleted over the useful lives of the related assets through charges to depreciation, and/or amortization. If the fair value of the estimated ARO changes, an adjustment is recorded to both the ARO and the asset retirement cost. Revisions in estimated liabilities can result from revisions of estimated inflation rates, escalating retirement costs, and changes in the estimated timing of settling ARO liabilities.
Fair Value of Financial Instruments	Fair Value of Financial Instruments We determine the fair value of financial instruments in accordance with ASC 820, Fair Value Measurements and Disclosures. ASC Topic 820 (“ASC 820”), Fair Value Measurements, establishes a valuation hierarchy for disclosure of the inputs to valuation techniques used to measure fair value. This standard describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value: • Level 1 inputs are unadjusted quoted prices in active markets for identical assets or liabilities. • Level 2 inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the assets or liabilities, either directly or indirectly, through market corroboration, for substantially the full term of the financial instrument. • Level 3 inputs are unobservable inputs based on assumptions used to measure assets or liabilities at fair value. Classification of an asset or liability within this hierarchy is determined based on the lowest level input that is significant to the fair value measurement. Valuation techniques used to measure fair value under ASC 820 must maximize the use of observable inputs and minimize the use of unobservable inputs. Cash and cash equivalents consists primarily of bank deposits or highly liquid short-term investments with a maturity of three months or less at the time of purchase. Restricted cash represents temporarily restricted deposits held as compensating balances against short-term borrowing arrangements. Cash, cash equivalents and restricted cash are based on Level 1 measurements. The carrying amounts of cash and cash equivalents, restricted cash, accounts receivable, other current assets, and accounts payable approximate fair value because of the short maturity of these instruments.
Revenue Recognition, Remaining Performance Obligations, and Disaggregation of Revenue	Revenue Recognition To determine the proper revenue recognition, we perform the following five steps: (a) identify the contract(s) with a customer; (b) identify the performance obligations in the contract; (c) determine the transaction price; (d) allocate the transaction price to the performance obligations in the contract; and (e) recognize revenue when (or as) we satisfy a performance obligation. We only apply the five-step model to contracts when it is probable that we will collect the consideration we are entitled to in exchange for the goods or services we transfer to the customer. The vast majority of revenues are from product sales to customers, pursuant to purchase orders with short lead times. Revenues from product sales are recognized when the customer obtains control of our product, which occurs at a point in time. The Company has elected to account for shipping and handling activities as a fulfillment cost as permitted by the standard. When we perform shipping and handling activities after the transfer of control to the customer (e.g. when control transfers prior to delivery), they are considered fulfillment activities, and accordingly, the costs are accrued when the related revenue is recognized. We expense incremental costs of obtaining a contract as and when incurred if the expected amortization period of the asset that we would have recognized is one year or less. In certain instances, inventory is maintained by customers at consigned locations. Revenues from consigned sales are recognized when the customer obtains control of our product, which occurs at a point in time. This is typically when the customer pulls product for use. We use a number of wholesale distributors around the world and recognize revenue when the wholesale distributor obtains control of our product, which occurs at a point in time, typically upon shipment. Wholesale distributors are contractually obligated to pay us on standard commercial terms, consistent with our end-use customers. We do not sell to wholesale distributors on consignment and do not give wholesale distributors a right of return. In certain instances, prior to customers accepting product that is manufactured at one of our CMs, these customers require that they first qualify the product and manufacturing processes at our CM (e.g. customer acceptance clause). The customers’ qualification process determines whether the product manufactured at our CM achieves their quality, performance, and reliability standards. After a customer completes the initial qualification process, we receive approval to ship qualified product to that customer. Revenues are recognized when the customer obtains control of the qualified product, which occurs at a point in time, typically upon shipment. To a lesser extent, we enter into other types of contracts including non-recurring engineering contracts. We recognize revenue for these arrangements over time or at a point in time depending on our evaluation of when the customer obtains control of the promised goods or services. For contracts that include multiple performance obligations, we allocate revenue to each performance obligation based on estimates of the relative standalone selling price that we would charge the customer for each promised product or service. Revenue from products and services transferred to customers over time accounted for 1%, 5%, and 4% of the Company’s revenue for the years ended September 30, 2021, 2020, and 2019, respectively. Remaining Performance Obligations Remaining performance obligations represent the transaction price of firm orders for long-term contracts which control has not transferred to the customer. As of September 30, 2021, the aggregate amount of the transaction price allocated to remaining performance obligations was $1.2 million. The Company expects to recognize revenue on approximately 100% of the remaining performance obligations over the next 12 months. Disaggregation of Revenue Revenue is classified within the Company’s segments. For additional information on the disaggregated revenues by geographical region and major product category, see Note 13 – Segment Data and Revenue Information in the Notes to Consolidated Financial Statements.
Receivables, Net	Receivables, Net Receivables, net, include amounts billed and currently due from customers. The amounts due are stated at their net estimated realizable value. Payments are generally due within 90 days or less of invoicing and do not include a significant financing component. We maintain an allowance for credit loss to provide for the estimated amount of receivables that will not be collected. The allowance is based upon an assessment of customer creditworthiness, historical payment experience, the age of outstanding receivables and collateral to the extent applicable. A contract asset is recognized when the Company has recognized revenue, but not issued an invoice for payment. Contract assets are classified as current assets and transferred to receivables when the entitlement to payment becomes unconditional. The Company’s contract assets are generally converted to trade account receivables within 90 days, at which time the Company is entitled to payment of the fixed price upon delivery of the finished product subject to customer payment terms.
Product Warranty Reserves	Product Warranty Reserves We provide customers with warranty claims for certain products and warranty-related services are not considered a separate performance obligation. Pursuant to ASC 450, Contingencies , we make estimates of product warranty expense using historical experience rates and accrue estimated warranty expense as a cost of revenue. We estimate the costs of warranty obligations based on historical experience of known product failure rates and anticipated rates of warranty claims, use of materials to repair or replace defective products, and service delivery costs incurred in correcting the product issues. In addition, from time to time, specific warranty accruals may be made if unforeseen technical problems arise.
Leases	Leases The Company adopted the new lease standard as of October 1, 2019 under the modified retrospective approach. Therefore, the consolidated financial statements for the year ended September 30, 2019 have not been adjusted and continued to be reported under previous U.S. GAAP guidance. Under the new lease standard, the Company determines if an arrangement is a lease at its inception. Right of use (ROU) assets and operating lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. The Company uses its estimated incremental borrowing rate in determining the present value of lease payments considering the term of the lease, which is derived from information available at the lease commencement date. The lease term includes renewal options when it is reasonably certain that the option will be exercised,
Recent Accounting Standards or Updates Not Yet Effective and Recently Adopted Accounting Pronouncements	Recent Accounting Standards or Updates Not Yet Effective In December 2019, the FASB issued Accounting Standards Update ("ASU") 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which simplifies the accounting for income taxes by removing various exceptions, such as the exception to the incremental approach for intra-period tax allocation when there is a loss from continuing operations and income or a gain from other items. The amendments in this update also simplify the accounting for income taxes related to income-based franchise taxes and require that an entity reflect enacted tax laws or rates in the annual effective tax rate computation in the interim period that includes the enactment date. The new standard is effective for annual periods beginning after December 15, 2020, including interim periods within those annual periods. This accounting standard is effective in the first quarter of the Company's fiscal year ended September 30, 2022. The Company does not expect the adoption of this new guidance to have a material impact on the condensed consolidated financial statements. Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which changes the way entities measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net earnings. The new standard was effective for our fiscal year beginning October 1, 2020. The adoption of this standard did not have a material impact on the condensed consolidated financial statements.
Legal Costs	Professional legal fees are expensed when incurred. We accrue for contingent losses when such losses are probable and reasonably estimable.

Cash, Cash Equivalents and Rest

Cash, Cash Equivalents and Restricted Cash (Tables)	12 Months Ended
	Sep. 30, 2021
Cash and Cash Equivalents [Abstract]
Schedule of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same amounts shown in the consolidated statements of cash flows: As of September 30, (in thousands) 2021 2020 2019 Cash $ 16,547 $ 11,325 $ 4,338 Cash equivalents 55,074 19,065 17,236 Restricted cash 61 148 403 Total cash, cash equivalents and restricted cash $ 71,682 $ 30,538 $ 21,977
Schedule of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same amounts shown in the consolidated statements of cash flows: As of September 30, (in thousands) 2021 2020 2019 Cash $ 16,547 $ 11,325 $ 4,338 Cash equivalents 55,074 19,065 17,236 Restricted cash 61 148 403 Total cash, cash equivalents and restricted cash $ 71,682 $ 30,538 $ 21,977

Accounts Receivable (Tables)

Accounts Receivable (Tables)	12 Months Ended
	Sep. 30, 2021
Receivables [Abstract]
Schedule of Accounts Receivable	The components of accounts receivable consisted of the following: As of September 30, (in thousands) 2021 2020 Accounts receivable, gross $ 32,109 $ 25,551 Allowance for credit loss (260) (227) Accounts receivable, net $ 31,849 $ 25,324 The following table summarizes changes in the allowance for credit loss: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Balance at beginning of period $ 227 $ 148 $ 548 Provision adjustment - expense, net of recoveries 90 188 62 Write-offs and other deductions (57) (109) (462) Balance at end of period $ 260 $ 227 $ 148

Inventory (Tables)

Inventory (Tables)	12 Months Ended
	Sep. 30, 2021
Inventory Disclosure [Abstract]
Schedule of Inventory	The components of inventory consisted of the following: As of September 30, (in thousands) 2021 2020 Raw materials $ 16,146 $ 13,354 Work in-process 11,410 8,381 Finished goods 4,753 3,790 Inventory balance at end of period $ 32,309 $ 25,525

Property, Plant, and Equipmen_2

Property, Plant, and Equipment, net (Tables)	12 Months Ended
	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	The components of property, plant, and equipment, net consisted of the following: As of September 30, (in thousands) 2021 2020 Equipment $ 37,985 $ 35,218 Furniture and fixtures 1,125 1,125 Computer hardware and software 3,575 3,473 Leasehold improvements 6,663 3,169 Construction in progress 9,247 10,301 Property, plant, and equipment, gross $ 58,595 $ 53,286 Accumulated depreciation (36,051) (32,234) Property, plant, and equipment, net $ 22,544 $ 21,052

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Sep. 30, 2021
Payables and Accruals [Abstract]
Schedule of Components of Accrued Expenses and Other Current Liabilities	The components of accrued expenses and other current liabilities consisted of the following: As of September 30, (in thousands) 2021 2020 Compensation $ 7,192 $ 6,916 Warranty 1,125 803 Legal expenses and other professional fees 152 211 Contract liabilities 364 502 Income and other taxes 104 1,265 Severance and restructuring accruals — 17 Other 999 1,863 Accrued expenses and other current liabilities $ 9,936 $ 11,577
Schedule of Product Warranty Accruals	The following table summarizes the changes in product warranty accrual accounts: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Balance at beginning of period $ 803 $ 654 $ 642 Provision for product warranty expense 505 626 186 Warranty liability assumed in acquisition liability — — 80 Adjustments and utilization of warranty accrual (183) (477) (254) Balance at end of period $ 1,125 $ 803 $ 654

Income and Other Taxes (Tables)

Income and Other Taxes (Tables)	12 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income (Loss) from Continuing Operations before Income Taxes	The Company’s income (loss) from operations before income taxes consisted of the following: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Domestic $ 25,744 $ (7,159) $ (35,100) Foreign 471 219 (830) Loss before income taxes $ 26,215 $ (6,940) $ (35,930)
Income Tax (Benefit) Expense	The Company’s income tax expense consisted of the following: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Federal: Current $ — $ 30 $ — Deferred — (43) — — (13) — State: Current 990 98 54 Deferred — (25) — 990 73 54 Foreign: Current (418) — — Deferred — — — (418) — — Total income tax expense $ 572 $ 60 $ 54
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the provision for income taxes, with the amount computed by applying the statutory U.S. federal and state income tax rates to continuing operations income before provision for income taxes is as follows: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Income tax expense (benefit) computed at U.S. federal statutory rate $ 5,506 $ (1,457) $ (7,540) State tax expense (benefit), net of U.S. federal effect 990 (156) (906) Foreign tax rate differential 24 13 (28) Effect due to change in tax rate — (137) (183) Shortfall from stock based compensation (122) 432 248 Other 103 94 223 Federal benefit on PPP loan forgiveness (1,363) — — Change in uncertain tax positions (419) — — State net operating loss carryforward adjustment 454 533 139 Change in valuation allowance (4,601) 738 8,101 Income tax expense $ 572 $ 60 $ 54 Effective tax rate 2.2 % 0.9 % 0.2 %
Schedule of Deferred Tax Assets and Liabilities	Significant components of deferred tax assets are as follows: As of September 30, (in thousands) 2021 2020 Federal net operating loss carryforwards $ 96,289 $ 100,363 Foreign net operating loss carryforwards 1,372 1,680 Income tax credit carryforwards 2,510 2,671 Inventory reserves 2,229 2,320 Accounts receivable reserves 62 55 Accrued warranty reserve 269 193 State net operating loss carryforwards 6,356 5,970 Stock compensation 979 806 Deferred compensation 476 443 Fixed assets and intangibles (497) (348) ROU lease liability 3,289 3,529 ROU lease assets (3,195) (3,467) Other 1,372 1,322 Total deferred tax assets 111,511 115,537 Valuation allowance (111,511) (115,537) Net deferred tax liabilities $ — $ —
Schedule of Change in Unrecognized Gross Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized gross tax benefits is as follows: (in thousands) Amount Balance as of September 30, 2019 $ 419 Adjustments based on tax positions related to the current year — Adjustments based on tax positions of prior years — Balance as of September 30, 2020 419 Adjustments based on tax positions related to the current year — Adjustments based on tax positions of prior years (419) Balance as of September 30, 2021 $ —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Schedule of Maturities of Operating Lease Liabilities	Maturities of operating lease liabilities as of September 30, 2021 were as follows: (in thousands) Amount 2022 $ 1,955 2023 1,856 2024 1,686 2025 1,730 2026 1,775 Thereafter 10,592 Total lease payments $ 19,594 Less imputed interest (5,712) Total $ 13,882
Schedule of Operating Lease Information	Weighted-average remaining lease term and discount rate related to operating leases are as follows: As of September 30, 2021 2020 Weighted average remaining lease term (years) 11.9 14.4 Weighted average discount rate 6.1 % 6.1 % Supplemental cash information and non-cash activities related to operating leases are as follows: As of September 30, (in thousands) 2021 2020 Operating cash outflows from operating leases $ 1,975 $ 1,592 Right-of-use assets obtained in exchange for operating lease liabilities $ 10,358 $ 10,791
Schedule of Change in Asset Retirement Obligation	The following table summarizes ARO activity: (in thousands) Amount Balance at September 30, 2020 $ 2,022 Accretion expense 48 Revision in estimated cash flows (21) Balance at September 30, 2021 $ 2,049

Equity (Tables)

Equity (Tables)	12 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Schedule of Stock Options Activity	The following table summarizes stock option activity under the Equity Plans for the fiscal year ended September 30, 2021: Number of Weighted Weighted Aggregate Outstanding as of September 30, 2020 44,065 $ 5.14 Granted — — Exercised (15,025) 5.13 Forfeited — — Expired (9,171) 6.35 Outstanding as of September 30, 2021 19,869 $ 4.59 3.75 $ 57 Exercisable as of September 30, 2021 19,869 $ 4.59 3.75 $ 57 Vested and expected to vest as of September 30, 2021 19,869 $ 4.59 3.75 $ 57 ___________________________________________ (*) Intrinsic value for stock options represents the “in-the-money” portion or the positive variance between a stock option’s exercise price and the underlying stock price. For the fiscal year ended September 30, 2020, the intrinsic value of options exercised was $0.
Schedule of Restricted Stock Activity	The following table summarizes the activity related to RSUs and RSAs subject to time-based vesting requirements for the fiscal year ended September 30, 2021: RSUs RSAs Number of Shares Weighted Number of Weighted Non-vested as of September 30, 2020 1,548,045 $ 3.41 8,154 $ 8.20 Granted 1,045,673 5.55 — — Vested (598,986) 3.43 (8,154) 8.20 Forfeited (189,878) 3.70 — — Non-vested as of September 30, 2021 1,804,854 $ 4.61 — $ —
Schedule of Performance Share Activity	The following table summarizes the activity related to PSUs for the fiscal year ended September 30, 2021: PSUs Number of Shares Weighted Average Grant Date Fair Value Non-vested as of September 30, 2020 868,500 $ 4.79 Granted 231,000 7.39 Vested (6,086) 7.91 Forfeited (126,414) 7.70 Non-vested as of September 30, 2021 967,000 $ 5.01
Schedule of Stock-based Compensation Expense - By Award Type	The following table set forth stock-based compensation expense by award type: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Employee stock options $ 2 $ 13 $ 25 RSUs and RSAs 2,093 1,755 1,495 PSUs and PRSAs 1,396 1,243 685 ESPP 307 214 180 Outside director equity awards and fees in common stock 382 291 221 Total stock-based compensation expense $ 4,180 $ 3,516 $ 2,606
Schedule of Stock-based Compensation Expense - By Expense Type	The following table set forth stock-based compensation expense by expense type: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Cost of revenue $ 767 $ 692 $ 482 Selling, general, and administrative 2,590 2,155 1,478 Research and development 823 669 646 Total stock-based compensation expense $ 4,180 $ 3,516 $ 2,606
Schedule of Earnings Per Share, Basic and Diluted	The following table sets forth the computation of basic and diluted earnings (loss) per share: For the Fiscal Year Ended September 30, (in thousands, except per share) 2021 2020 2019 Numerator Net income (loss) $ 25,643 $ (7,000) $ (35,984) Denominator Weighted average number of shares outstanding - basic 34,020 29,136 27,983 Effect of dilutive securities Stock options 7 — — PSUs, RSUs, and restricted stock 1,762 — — Weighted average number of shares outstanding - diluted 35,789 29,136 27,983 Earnings (loss) per share - basic $ 0.75 $ (0.24) $ (1.29) Earnings (loss) per share - diluted $ 0.72 $ (0.24) $ (1.29) Weighted average antidilutive options, unvested RSUs and RSAs, unvested PSUs and ESPP shares excluded from the computation 195 1,109 810
Schedule of Common Stock Reserved for Future Issuances	As of September 30, 2021, we had common stock reserved for the following future issuances: Number of Common Exercise of outstanding stock options 19,869 Unvested RSUs and RSAs 1,804,854 Unvested PSUs and PRSAs (at 200% maximum payout) 1,934,000 Issuance of stock-based awards under the Equity Plans 1,751,234 Purchases under the officer and director share purchase plan 88,741 Total reserved 5,598,698

Segment and Revenue Informati_2

Segment and Revenue Information (Tables)	12 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Schedule of Reportable Segment	Information on reportable segments utilized by the chief operating decision maker is as follows: (in thousands) For the Fiscal Year Ended September 30, 2021 2020 2019 Revenue Aerospace and Defense $ 50,838 $ 55,240 $ 33,086 Broadband 107,606 54,888 54,179 Total revenue $ 158,444 $ 110,128 $ 87,265 Segment income (loss) Aerospace and Defense gross profit $ 13,705 $ 16,729 $ 9,207 Aerospace and Defense research and development expense 14,616 17,469 10,448 Aerospace and Defense segment loss $ (911) $ (740) $ (1,241) Broadband gross profit $ 47,783 $ 18,853 $ 5,882 Broadband research and development expense 2,832 2,800 8,995 Broadband segment income (loss) $ 44,951 $ 16,053 $ (3,113) Consolidated segment income (loss) $ 44,040 $ 15,313 $ (4,354) Unallocated operating expense Selling, general, and administrative $ 24,544 $ 24,631 $ 32,080 Loss (gain) on sale of assets 515 (2,284) (302) Total unallocated operating expense $ 25,059 $ 22,347 $ 31,778 Operating income (loss) $ 18,981 $ (7,034) $ (36,132)
Revenue by Major Product Category	Revenue is also classified by major product category and is presented below: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 Aerospace and Defense Navigation and Inertial Sensing $ 36,539 $ 38,983 $ 23,203 Defense Optoelectronics 14,299 16,257 9,883 Broadband CATV Lasers and Transmitters 95,255 44,457 41,150 Chip Devices 3,106 4,873 10,828 Other Optical Products 9,245 5,558 2,201 Total revenue $ 158,444 $ 110,128 $ 87,265
Schedule of Revenue by Geographic Region	The following table sets forth revenue by geographic area based on customers’ billing address: For the Fiscal Year Ended September 30, (in thousands) 2021 2020 2019 United States and Canada $ 139,443 $ 91,205 $ 68,607 Asia 11,836 9,397 11,637 Europe 4,802 5,559 6,209 Other 2,363 3,967 812 Total revenue $ 158,444 $ 110,128 $ 87,265

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Property, Plant, and Equipment (Details)	12 Months Ended
	Sep. 30, 2021
Equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	3 years
Equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	10 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	5 years
Computer hardware and software | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	5 years
Computer hardware and software | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	7 years

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Revenue Recognition (Details)	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Revenue From Products And Services Transferred Over Time Risk | Revenue Benchmark | Transferred over time
Disaggregation of Revenue [Line Items]
Concentration risk percentage	1.00%	5.00%	4.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Performance Obligations (Details) $ in Millions	Sep. 30, 2021USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Transaction price allocated to performance obligation	$ 1.2
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, percentage	100.00%
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months

Cash, Cash Equivalents and Re_2

Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Cash and Cash Equivalents [Abstract]
Cash	$ 16,547	$ 11,325	$ 4,338
Cash equivalents	55,074	19,065	17,236
Restricted cash	61	148	403
Total cash, cash equivalents and restricted cash	$ 71,682	$ 30,538	$ 21,977

Accounts Receivable - Schedule

Accounts Receivable - Schedule of Components of Accounts Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Receivables [Abstract]
Accounts receivable, gross	$ 32,109	$ 25,551
Allowance for credit loss	(260)	(227)
Accounts receivable, net	$ 31,849	$ 25,324

Accounts Receivable - Allowance

Accounts Receivable - Allowance for Credit Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 227	$ 148	$ 548
Provision adjustment - expense, net of recoveries	90	188	62
Write-offs and other deductions	(57)	(109)	(462)
Balance at end of period	$ 260	$ 227	$ 148

Inventory - Schedule of Compone

Inventory - Schedule of Components of Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Inventory Disclosure [Abstract]
Raw materials	$ 16,146	$ 13,354
Work in-process	11,410	8,381
Finished goods	4,753	3,790
Inventory balance at end of period	$ 32,309	$ 25,525

Property, Plant, and Equipmen_3

Property, Plant, and Equipment, net - Schedule of Property, Plant, and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	$ 58,595	$ 53,286
Accumulated depreciation	(36,051)	(32,234)
Property, plant, and equipment, net	22,544	21,052
Equipment
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	37,985	35,218
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	1,125	1,125
Computer hardware and software
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	3,575	3,473
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	6,663	3,169
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	$ 9,247	$ 10,301

Property, Plant and Equipment,

Property, Plant and Equipment, net - Narrative (Details) - USD ($) $ in Thousands	Feb. 10, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Property, Plant and Equipment [Line Items]
Depreciation		$ 4,000	$ 5,500	$ 7,100
Gain (loss) on sale of equipment		(500)	2,300
Assets held for sale		$ 1,241	1,568
Sale leaseback, transaction price	$ 13,200
Proceeds from sale of leasebacks	$ 12,800
Sale and leaseback transaction, gain (loss), net			300
Additional operating lease right use of assets			10,800
Additional operating right use of liabilities			$ 10,800
United States | Long-lived assets | Geographic Concentration Risk
Property, Plant and Equipment [Line Items]
Concentration risk percentage		96.00%	97.00%

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Payables and Accruals [Abstract]
Compensation	$ 7,192	$ 6,916
Warranty	1,125	803
Legal expenses and other professional fees	152	211
Contract liabilities	364	502
Income and other taxes	104	1,265
Severance and restructuring accruals	0	17
Other	999	1,863
Accrued expenses and other current liabilities	$ 9,936	$ 11,577

Accrued Expenses and Other Cu_4

Accrued Expenses and Other Current Liabilities - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Payables and Accruals [Abstract]
Severance expense	$ 0.1	$ 0.6	$ 0.5

Accrued Expenses and Other Cu_5

Accrued Expenses and Other Current Liabilities - Schedule of Product Warranty Accruals (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 803	$ 654	$ 642
Provision for product warranty expense	505	626	186
Warranty liability assumed in acquisition liability	0	0	80
Adjustments and utilization of warranty accrual	(183)	(477)	(254)
Balance at end of period	$ 1,125	$ 803	$ 654

Credit Facility and Debt - Narr

Credit Facility and Debt - Narrative (Details)	May 06, 2020USD ($)	Sep. 30, 2021USD ($)credit
Paycheck Protection Program
Line of Credit Facility [Line Items]
Proceeds from Paycheck Protection Program - CARES Act	$ 6,500,000
PPP loan balance - CARES Act		$ 0
Revolving Credit Facility
Line of Credit Facility [Line Items]
Liquidity requirement, minimum after specific uses		25,000,000
Liquidity requirement, minimum		10,000,000
Excess availability requirement, minimum		1,000,000
Long-term line of credit		0
Standby letters of credit, total amount outstanding		500,000
Line of credit facility, remaining borrowing capacity		13,400,000
Revolving Credit Facility | Tenth Amendment
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity		$ 15,000,000
Revolving Credit Facility | Tenth Amendment | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on variable rate		1.75%
Revolving Credit Facility | LIBOR Rate Loan
Line of Credit Facility [Line Items]
Number of standby letters of credit outstanding | credit		1

Income and Other Taxes - Contin

Income and Other Taxes - Continuing Operations before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Domestic	$ 25,744	$ (7,159)	$ (35,100)
Foreign	471	219	(830)
Income (loss) before income tax expense	$ 26,215	$ (6,940)	$ (35,930)

Income and Other Taxes - Income

Income and Other Taxes - Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Current federal tax expense (benefit)	$ 0	$ 30	$ 0
Deferred federal income tax expense (benefit)	0	(43)	0
Total federal income tax expense (benefit)	0	(13)	0
Current state tax expense (benefit)	990	98	54
Deferred state tax expense (benefit)	0	(25)	0
Total state income tax expense (benefit)	990	73	54
Current foreign tax expense (benefit)	(418)	0	0
Deferred foreign tax expense (benefit)	0	0	0
Total foreign income tax expense (benefit)	(418)	0	0
Total income tax expense	$ 572	$ 60	$ 54

Income and Other Taxes - Provis

Income and Other Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income tax expense (benefit) computed at U.S. federal statutory rate	$ 5,506	$ (1,457)	$ (7,540)
State tax expense (benefit), net of U.S. federal effect	990	(156)	(906)
Foreign tax rate differential	24	13	(28)
Effect due to change in tax rate	0	(137)	(183)
Shortfall from stock based compensation	(122)	432	248
Other	103	94	223
Federal benefit on PPP loan forgiveness	(1,363)	0	0
Change in uncertain tax positions	(419)	0	0
State net operating loss carryforward adjustment	454	533	139
Change in valuation allowance	(4,601)	738	8,101
Total income tax expense	$ 572	$ 60	$ 54
Effective tax rate (percentage)	2.20%	0.90%	0.20%

Income and Other Taxes - Deferr

Income and Other Taxes - Deferred Tax Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Federal net operating loss carryforwards	$ 96,289	$ 100,363
Foreign net operating loss carryforwards	1,372	1,680
Income tax credit carryforwards	2,510	2,671
Inventory reserves	2,229	2,320
Accounts receivable reserves	62	55
Accrued warranty reserve	269	193
State net operating loss carryforwards	6,356	5,970
Stock compensation	979	806
Deferred compensation	476	443
Fixed assets and intangibles	(497)	(348)
ROU lease liability	3,289	3,529
ROU lease assets	(3,195)	(3,467)
Other	1,372	1,322
Total deferred tax assets	111,511	115,537
Valuation allowance	(111,511)	(115,537)
Net deferred tax liabilities	$ 0	$ 0

Income and Other Taxes - Narrat

Income and Other Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Operating Loss Carryforwards [Line Items]
Income tax expense	$ 572	$ 60	$ 54
Effective tax rate on continuing operations	2.20%	0.90%	0.20%
Portion of operating loss carryforward subject to limitation	$ 230,200
Portion of operating loss carryforward not subject to limitation	228,300
Interest and penalties accrued as tax liabilities	0	$ 600
Foreign Income And Research And Development Credit
Operating Loss Carryforwards [Line Items]
Tax credit	2,500
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	458,500
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	5,500
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 72,800

Income and Other Taxes - Unreco

Income and Other Taxes - Unrecognized Gross Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning of period	$ 419	$ 419
Adjustments based on tax positions related to the current year	0	0
Adjustments based on tax positions of prior years	(419)	0
End of period	$ 0	$ 419

Commitments and Contingencies -

Commitments and Contingencies - Leases and Asset Retirement Obligations Narrative (Details) - USD ($)	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Loss Contingencies [Line Items]
Lease option to extend length (in years)	5 years
Operating lease expenses	$ 2,200,000	$ 1,800,000
ARO liability	$ 2,049,000	2,022,000
Risk-free rate, minimum	0.06%
Risk-free rate, maximum	1.73%
Accretion expense	$ 47,600	31,900	$ 54,200
Minimum
Loss Contingencies [Line Items]
Operating lease, remaining lease term	7 months 6 days
Maximum
Loss Contingencies [Line Items]
Operating lease, remaining lease term	13 years 4 months 24 days
Property in Alhambra, California
Loss Contingencies [Line Items]
ARO liability	$ 2,000,000	$ 2,000,000

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Lease Maturities (Details) $ in Thousands	Sep. 30, 2021USD ($)
Commitments and Contingencies Disclosure [Abstract]
2022	$ 1,955
2023	1,856
2024	1,686
2025	1,730
2026	1,775
Thereafter	10,592
Total lease payments	19,594
Less imputed interest	(5,712)
Total	$ 13,882

Commitments and Contingencies_3

Commitments and Contingencies - Additional Lease Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Weighted average remaining lease term (years)	11 years 10 months 24 days	14 years 4 months 24 days
Weighted average discount rate	6.10%	6.10%
Operating cash outflows from operating leases	$ 1,975	$ 1,592
Right-of-use assets obtained in exchange for operating lease liabilities	$ 10,358	$ 10,791

Commitments and Contingencies_4

Commitments and Contingencies - ARO Rollforward (Details) - USD ($)	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 2,022,000
Accretion expense	47,600	$ 31,900	$ 54,200
Revision in estimated cash flows	(21,000)
Ending balance	$ 2,049,000	$ 2,022,000

Commitments and Contingencies_5

Commitments and Contingencies - Legal Proceedings (Details)	Oct. 10, 2019USD ($)	Oct. 01, 2019USD ($)	Jun. 21, 2019USD ($)productclaim	Apr. 30, 2021USD ($)	Dec. 31, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Feb. 10, 2021	Jul. 31, 2020USD ($)	Apr. 30, 2020USD ($)	Jan. 31, 2020USD ($)
Phoenix Navigation Components, LLC Legal Proceedings
Loss Contingencies [Line Items]
Total damages sought			$ 21,200,000
Number of deemed trade secrets used | claim			1
Number of products using deemed trade secrets | product			7
Royalties owed (as percentage of sale price)			7.50%
Amount awarded to other party					$ 400,000	$ 400,000	$ 3,800,000
Reduction of attorneys' fees owed (as a percent)			10.00%
Royalty payments			$ 1,000,000
Royalties owed after first $1 million of payments (as a percentage of sale price)			2.25%
Loss contingency accrual									$ 100,000	$ 100,000	$ 200,000
Payments for Legal Settlements	$ 4,500,000
Legal fees							$ 5,700,000
Phoenix Navigation Components, LLC Legal Proceedings | Trade Secrets
Loss Contingencies [Line Items]
Number of pending claims | claim			97
Number of claims settled | claim			5
Phoenix Navigation Components, LLC Legal Proceedings | Legal Expense
Loss Contingencies [Line Items]
Amount awarded to other party		$ 3,800,000	$ 3,700,000
Phoenix Navigation Components, LLC Legal Proceedings | Royalty
Loss Contingencies [Line Items]
Amount awarded to other party		1,000,000
Loss contingency accrual		600,000
Phoenix Navigation Components, LLC Legal Proceedings | Interest
Loss Contingencies [Line Items]
Amount awarded to other party		$ 100,000
Resilience Litigation | Resilience Capital
Loss Contingencies [Line Items]
Total damages sought				$ 1,565,000
Resilience Litigation | Concord Property
Loss Contingencies [Line Items]
Lease length in years								15 years

Equity - Narrative (Details)

Equity - Narrative (Details)	Feb. 16, 2021USD ($)$ / sharesshares	Mar. 31, 2021shares	Sep. 30, 2021USD ($)plan$ / sharesshares	Sep. 30, 2020USD ($)$ / sharesshares	Sep. 30, 2019USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity incentive compensation plans maintained by the company | plan			3
Granted (in shares)			0	0
Common stock, shares authorized (in shares)			50,000,000	50,000,000
Common stock, no par value (in dollars per share) | $ / shares			$ 0	$ 0
Preferred stock, shares authorized (in shares)			5,882,352
Preferred stock par value (in usd per share) | $ / shares			$ 0.0001
Common stock, shares issued (in shares)			43,890,000	36,461,000
Preferred stock, shares issued (in shares)			0	0
Preferred stock, outstanding (in shares)			0	0
Matching contribution | $			$ 1,100,000	$ 1,000,000	$ 600,000
Aggregate common shares issued under ESPP (in shares)			3,395,090
Shares remaining available for issuance under the ESPP (in shares)			0
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock - ESPP (in shares)			192,000	231,000	197,000
Common Stock | IPO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sale of Stock, Number of Shares Issued in Transaction	6,655,093
Sale of Stock, Price Per Share | $ / shares	$ 5.40
Proceeds from Issuance Initial Public Offering | $	$ 33,100,000
Common Stock | Over-Allotment Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sale of Stock, Number of Shares Issued in Transaction	868,056
2019 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional number of shares authorized for the plan (in shares)		2,138,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ESPP offering period (months)			6 months
Purchase price (as percentage of market price)			85.00%
Annual contribution (as percentage of compensation)			10.00%
Annual contribution | $			$ 25,000
Employee stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, average minimum vesting period (in years)			4 years
Stock options, average maximum vesting period (in years)			5 years
Stock options, contractual life (in years)			10 years
RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested stock units (in shares)			0	8,154
Intrinsic value vested | $			$ 27,300
Weighted average fair value (in usd per share) | $ / shares			$ 0
RSAs | Equity Incentive Plans 2012 and 2010 | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			3 years
RSAs | Equity Incentive Plans 2012 and 2010 | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			4 years
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized stock-based compensation expense | $			$ 6,700,000
Weighted average remaining service period (in years)			2 years 8 months 12 days
Unvested stock units (in shares)			1,804,854	1,548,045
Unvested stock units | $			$ 13,500,000
Unvested stock units weighted average remaining contractual term (in years)			2 years 8 months 12 days
Intrinsic value vested | $			$ 3,600,000	$ 1,300,000	$ 1,400,000
Weighted average fair value (in usd per share) | $ / shares			$ 5.55	$ 3.41	$ 3.68
PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining service period (in years)			1 year 3 months 18 days
Unvested stock units (in shares)			967,000	868,500
Intrinsic value vested | $			$ 34,400	$ 0	$ 200,000
Weighted average fair value (in usd per share) | $ / shares			$ 7.39	$ 3.81	$ 5.19
Unamortized stock-based compensation expense | $			$ 2,400,000
Intrinsic value of non-vested and expected to vest PSUs | $			$ 7,200,000
Average remaining contractual term (in years)			1 year 3 months 18 days
PSUs | Two Thousand Twelve Equity Incentive Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			1 year
PSUs | Two Thousand Twelve Equity Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			3 years
PRSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized stock-based compensation expense | $				$ 0

Equity - Schedule of Stock Opti

Equity - Schedule of Stock Options Activity (Details) - USD ($)	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Number of Shares
Outstanding, beginning of period (in shares)	44,065
Granted (in shares)	0	0
Exercised (in shares)	(15,025)
Forfeited (in shares)	0
Expired (in shares)	(9,171)
Outstanding, end of period (in shares)	19,869	44,065
Exercisable (in shares)	19,869
Vested and expected to vest (in shares)	19,869
Weighted Average Exercise Price
Outstanding, beginning of period (in usd per share)	$ 5.14
Granted (in usd per share)	0
Exercised (in usd per share)	5.13
Forfeited (in usd per share)	0
Expired (in usd per share)	6.35
Outstanding, ending of period (in usd per share)	4.59	$ 5.14
Exercisable (in usd per share)	4.59
Vested and expected to vest (in usd per share)	$ 4.59
Weighted Average Remaining Contractual Life (in years)
Weighted average remaining contractual life, outstanding (in years)	3 years 9 months
Weighted average remaining contractual life, exercisable (in years)	3 years 9 months
Weighted average remaining contractual term, vested and expected to vest (in years)	3 years 9 months
Aggregate Intrinsic Value
Outstanding, Aggregate intrinsic value	$ 57,000
Exercisable, Aggregate intrinsic value	57,000
Vested and expected to vest, Aggregate intrinsic value	$ 57,000
Intrinsic value of options exercised		$ 0

Equity - Schedule of Restricted

Equity - Schedule of Restricted Stock Activity (Details) - $ / shares	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
RSUs
Number of Shares
Non-vested, beginning balance (in shares)	1,548,045
Granted (in shares)	1,045,673
Vested (in shares)	(598,986)
Forfeited (in shares)	(189,878)
Non-vested, ending balance (in shares)	1,804,854	1,548,045
Weighted Average Grant Date Fair Value
Non-vested, beginning balance (in usd per share)	$ 3.41
Weighted average fair value (in usd per share)	5.55	$ 3.41	$ 3.68
Vested (in usd per share)	3.43
Forfeited (in usd per share)	3.70
Non-vested, ending balance (in usd per share)	$ 4.61	$ 3.41
RSAs
Number of Shares
Non-vested, beginning balance (in shares)	8,154
Granted (in shares)	0
Vested (in shares)	(8,154)
Forfeited (in shares)	0
Non-vested, ending balance (in shares)	0	8,154
Weighted Average Grant Date Fair Value
Non-vested, beginning balance (in usd per share)	$ 8.20
Weighted average fair value (in usd per share)	0
Vested (in usd per share)	8.20
Forfeited (in usd per share)	0
Non-vested, ending balance (in usd per share)	$ 0	$ 8.20

Equity - Schedule of Performanc

Equity - Schedule of Performance Stock Activity (Details) - PSUs - $ / shares	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Number of Shares
Non-vested, beginning balance (in shares)	868,500
Granted (in shares)	231,000
Vested (in shares)	(6,086)
Forfeited (in shares)	(126,414)
Non-vested, ending balance (in shares)	967,000	868,500
Weighted Average Grant Date Fair Value
Non-vested, beginning balance (in usd per share)	$ 4.79
Granted (in usd per share)	7.39	$ 3.81	$ 5.19
Vested (in usd per share)	7.91
Forfeited (in usd per share)	7.70
Non-vested, ending balance (in usd per share)	$ 5.01	$ 4.79

Equity - Schedule of Stock-base

Equity - Schedule of Stock-based Compensation Expense - by Award Type (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 4,180	$ 3,516	$ 2,606
Employee stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	2	13	25
RSUs and RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	2,093	1,755	1,495
PSUs and PRSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	1,396	1,243	685
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	307	214	180
Outside director equity awards and fees in common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 382	$ 291	$ 221

Equity - Schedule of Stock-ba_2

Equity - Schedule of Stock-based Compensation Expense - by Expense Category (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 4,180	$ 3,516	$ 2,606
Cost of revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	767	692	482
Selling, general, and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	2,590	2,155	1,478
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 823	$ 669	$ 646

Equity - Schedule of Earnings p

Equity - Schedule of Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net income (loss)	$ 25,643	$ (7,000)	$ (35,984)
Denominator
Weighted average number of shares outstanding - basic (in shares)	34,020	29,136	27,983
Effect of dilutive securities
Weighted average number of shares outstanding - diluted (in shares)	35,789	29,136	27,983
Earnings (loss) per share - basic (in dollars per share)	$ 0.75	$ (0.24)	$ (1.29)
Earnings (loss) per share - diluted (in dollars per share)	$ 0.72	$ (0.24)	$ (1.29)
Weighted average antidilutive options, unvested restricted stock units and awards, unvested performance stock units and ESPP shares excluded from the computation (in shares)	195	1,109	810
Employee stock options
Effect of dilutive securities
Dilutive options outstanding, unvested stock units and unvested stock awards (in shares)	7	0	0
PSUs, RSUs, and restricted stock
Effect of dilutive securities
Dilutive options outstanding, unvested stock units and unvested stock awards (in shares)	1,762	0	0

Equity - Schedule of Common Sto

Equity - Schedule of Common Stock Reserved for Future Issuances (Details) - shares	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise of outstanding stock options (in shares)	19,869	44,065
Issuance of stock-based awards under the Equity Plans (in shares)	1,751,234
Purchases under the officer and director share purchase plan (in shares)	88,741
Total reserved (in shares)	5,598,698
RSUs and RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested stock units (in shares)	1,804,854
PSUs and PRSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested award potential, percentage	200.00%
Unvested performance stock units (in shares)	1,934,000

Segment and Revenue Informati_3

Segment and Revenue Information - Schedule of Reportable Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenue	$ 158,444	$ 110,128	$ 87,265
Gross profit	61,488	35,582	15,089
R&D expense	17,448	20,269	19,443
Unallocated operating expense
Selling, general, and administrative	24,544	24,631	32,080
Loss (gain) on sale of assets	515	(2,284)	(302)
Total unallocated operating expense	25,059	22,347	31,778
Operating income (loss)	18,981	(7,034)	(36,132)
Operating Segments
Segment Reporting Information [Line Items]
Revenue	158,444	110,128	87,265
Segment income (loss)	44,040	15,313	(4,354)
Aerospace and Defense | Operating Segments
Segment Reporting Information [Line Items]
Revenue	50,838	55,240	33,086
Gross profit	13,705	16,729	9,207
R&D expense	14,616	17,469	10,448
Segment income (loss)	(911)	(740)	(1,241)
Broadband | Operating Segments
Segment Reporting Information [Line Items]
Revenue	107,606	54,888	54,179
Gross profit	47,783	18,853	5,882
R&D expense	2,832	2,800	8,995
Segment income (loss)	$ 44,951	$ 16,053	$ (3,113)

Segment and Revenue Informati_4

Segment and Revenue Information - Revenue by Category (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 158,444	$ 110,128	$ 87,265
Navigation and Inertial Sensing | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Revenue	36,539	38,983	23,203
Defense Optoelectronics | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Revenue	14,299	16,257	9,883
CATV Lasers and Transmitters | Broadband
Disaggregation of Revenue [Line Items]
Revenue	95,255	44,457	41,150
Chip Devices | Broadband
Disaggregation of Revenue [Line Items]
Revenue	3,106	4,873	10,828
Other Optical Products | Broadband
Disaggregation of Revenue [Line Items]
Revenue	$ 9,245	$ 5,558	$ 2,201

Segment and Revenue Informati_5

Segment and Revenue Information - Schedule of Revenue by Geographic Region (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Segment revenue	$ 158,444	$ 110,128	$ 87,265
United States and Canada
Segment Reporting Information [Line Items]
Segment revenue	139,443	91,205	68,607
Asia
Segment Reporting Information [Line Items]
Segment revenue	11,836	9,397	11,637
Europe
Segment Reporting Information [Line Items]
Segment revenue	4,802	5,559	6,209
Other
Segment Reporting Information [Line Items]
Segment revenue	$ 2,363	$ 3,967	$ 812

Segment and Revenue Informati_6

Segment and Revenue Information - Narrative (Details)	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Customer Concentration Risk | Sales Revenue, Segment | Three Significant Customers
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Concentration risk percentage	70.00%	57.00%	55.00%

Subsequent Events (Details)

Subsequent Events (Details)	12 Months Ended
	Sep. 30, 2023USD ($)	Sep. 30, 2022USD ($)	Nov. 01, 2021	Sep. 30, 2021
Subsequent Event [Line Items]
Lease option to extend length (in years)				5 years
Subsequent Event | Building
Subsequent Event [Line Items]
Lease option to extend length (in years)			5 years
Subsequent Event | Forecast | Building
Subsequent Event [Line Items]
Lease, base monthly rent	$ 53,500	$ 51,500
Lease, monthly base rent, percentage term	0.02