Westell (WSTL) 10-Q 9 Feb 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Dec. 31, 2017	Jan. 26, 2018
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Entity Registrant Name	WESTELL TECHNOLOGIES INC
Entity Central Index Key	1,002,135
Current Fiscal Year End Date	--03-31
Entity Filer Category	Smaller Reporting Company
Class A Common Stock
Entity Common Stock, Shares Outstanding		12,117,569
Class B Common Stock
Entity Common Stock, Shares Outstanding		3,484,287

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($)	Dec. 31, 2017		Mar. 31, 2017
Current assets:
Cash and cash equivalents	$ 21,492,000	[1]	$ 21,778,000
Short-term Investments	4,537,000		0
Accounts receivable (net of allowance of $90 at December 31, 2017, and March 31, 2017)	11,070,000		12,075,000
Inventories	9,464,000		12,511,000
Prepaid expenses and other current assets	864,000		1,409,000
Total current assets	47,427,000		47,773,000
Land, property and equipment, gross	9,023,000		16,062,000
Less accumulated depreciation and amortization	(7,393,000)		(14,078,000)
Land, property and equipment, net	1,630,000		1,984,000
Intangible assets, net	12,482,000		15,624,000
Income Taxes Receivable	697,000
Other non-current assets	80,000		160,000
Total assets	62,316,000		65,541,000
Current liabilities:
Accounts payable	2,494,000		4,163,000
Accrued expenses	3,528,000		4,273,000
Restructuring Reserve, Current	166,000		1,171,000
Deferred revenue	1,931,000		2,359,000
Total current liabilities	8,119,000		11,966,000
Deferred revenue non-current	912,000		1,102,000
Restructuring Reserve, Noncurrent	0		63,000
Other non-current liabilities	341,000		236,000
Total liabilities	9,372,000		13,367,000
Commitments and contingencies (Note 9)
Stockholders’ equity:
Preferred stock, par $0.01, Authorized - 1,000,000 shares. Issued and outstanding - none	0		0
Additional paid-in capital	417,408,000		416,422,000	[2]
Treasury stock at cost – 4,628,795 and 4,440,600(1) shares at December 31, 2017, and March 31, 2017, respectively	(35,891,000)		(35,335,000)
Cumulative translation adjustment	0		608,000
Accumulated deficit	(328,729,000)		(329,676,000)
Total stockholders’ equity	52,944,000		52,174,000
Total liabilities and stockholders’ equity	62,316,000		65,541,000
Class A Common Stock
Stockholders’ equity:
Common stock, value	121,000		120,000	[2]
Class B Common Stock
Stockholders’ equity:
Common stock, value	$ 35,000		$ 35,000	[2]
[1]	As of December 31, 2017, the Company has $4.5 million of short-term investments in addition to cash and cash equivalents.
[2]	All common stock (except authorized shares), equity share, and per share amounts have been retroactively adjusted to reflect a one-for-four reverse stock split, which was effective June 7, 2017.

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Mar. 31, 2017
Accounts receivable, allowance	$ 90	$ 90
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Treasury stock, shares	4,628,795	4,440,600	[1]
Class A Common Stock
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	109,000,000	109,000,000
Common stock, shares outstanding	12,117,569	12,015,043	[1]
Class B Common Stock
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	25,000,000	25,000,000
Common stock, shares issued	3,484,287	3,484,287	[1]
Common stock, shares outstanding	3,484,287	3,484,287	[1]
[1]	All common stock (except authorized shares), equity share, and per share amounts have been retroactively adjusted to reflect a one-for-four reverse stock split, which was effective June 7, 2017.

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended				9 Months Ended
		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2017		Dec. 31, 2016
Sales Revenue, Goods, Net		$ 11,754		$ 12,746		$ 43,396		$ 42,240
Sales Revenue, Services, Net		1,921		2,237		4,085		5,339
Total revenue		13,675		14,983		47,481		47,579
Cost of Goods Sold		7,114		7,807		26,060		27,788	[1]
Cost of Services		485		1,122		1,303		2,805
Total cost of revenue		7,599		8,929		27,363		30,593	[1]
Gross profit		6,076		6,054		20,118		16,986	[1]
Operating expenses
Research and development		1,542		2,414		6,023		10,018
Sales and marketing		1,950		1,943		6,278		8,220
General and administrative		1,502		1,777		5,022		6,340
Intangible amortization		1,047		1,212		3,142		3,613
Restructuring				490		165		3,055
Impairment of Long-Lived Assets to be Disposed of		0		0		0		1,181
Total operating expenses		6,041		7,836		20,630		32,427
Operating profit (loss)		35		(1,782)		(512)		(15,441)
Other income, net		79		(15)		799	[2]	76
Income (loss) before income taxes		114		(1,797)		287		(15,365)
Income tax benefit (expense)		685	[3]	(10)		660	[3]	(20)
Net income (loss)		$ 799		$ (1,807)		$ 947		$ (15,385)
Net income (loss) per share:
Basic		$ 0.05		$ (0.12)	[4]	$ 0.06		$ (1)	[4]
Diluted		$ 0.05		$ (0.12)	[4]	$ 0.06		$ (1)	[4]
Weighted-average number of common shares outstanding:
Basic (shares)		15,504		15,391	[4]	15,482		15,315	[4]
Effect of dilutive securities: restricted stock, restricted stock units, performance stock units and stock options (5)	[5]	251		0		197		0
Diluted (shares)		15,755		15,391	[4]	15,679		15,315	[4]
[1]	The nine months ended December 31, 2016, includes $1.6 million of E&O expense for ClearLink DAS inventory and pipeline inventory.
[2]	During the quarter ended September 30, 2017, the Company dissolved the NoranTel legal entity, which triggered a one-time foreign currency gain with the reversal of a cumulative translation adjustment. See Note 1.
[3]	During the quarter ended December 31, 2017, the Company had income tax benefit from the release of the tax valuation allowance associated with previously generated alternative minimum tax (AMT) credits due to the enacted Tax Reform. See Note 8.
[4]	All common stock (except authorized shares), equity share, and per share amounts have been retroactively adjusted to reflect a one-for-four reverse stock split, which was effective June 7, 2017.
[5]	The Company had 0.2 million and 0.4 million shares represented by common stock equivalents for the three and nine months ended December 31, 2017, and 1.0 million and 1.3 million shares represented by common stock equivalents for the three and nine months ended December 31, 2016, which were not included in the computation of average dilutive shares outstanding because they were anti-dilutive. In periods with a net loss from continuing operations, the basic loss per share equals the diluted loss per share as all common stock equivalents are excluded from the per share calculation.

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Operations (Unaudited) Condensed Consolidated Statements of Operations Parenthetical (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Production Related Impairments or Charges				$ 1.6
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.2	1	0.4	1.3

Condensed Statements of Compreh

Condensed Statements of Comprehensive Income ( Loss) (Unaudited) Statement - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017		Dec. 31, 2016
Net income (loss)	$ 799	$ (1,807)	$ 947		$ (15,385)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax	0	0	(608)	[1]	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 799	$ (1,807)	$ 339		$ (15,385)
[1]	During the quarter ended September 30, 2017, the Company dissolved the NoranTel legal entity, which triggered a one-time foreign currency gain with the reversal of a cumulative translation adjustment. See Note 1.

Condensed Statements of Stockho

Condensed Statements of Stockholders' Equity (Unaudited) Statement - 9 months ended Dec. 31, 2017 - USD ($) $ in Thousands		Total	Common Stock [Member]Common Class A [Member]		Common Stock [Member]Common Class B [Member]		Additional Paid-in Capital [Member]		Treasury Stock [Member]	Accumulated Foreign Currency Adjustment Attributable to Parent [Member]	Retained Earnings [Member]
Stockholders' Equity Attributable to Parent at Mar. 31, 2017		$ 52,174	$ 120	[1]	$ 35	[1]	$ 416,422	[1]	$ (35,335)	$ 608	$ (329,676)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		947									947
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax	[2]	(608)								(608)
Stock Issued During Period, Value, Share-based Compensation, Gross		1	3				(2)
Treasury Stock, Value, Acquired, Cost Method		(558)	(2)						(556)
Stock-based compensation		988					988
Stockholders' Equity Attributable to Parent at Dec. 31, 2017		$ 52,944	$ 121		$ 35		$ 417,408		$ (35,891)	$ 0	$ (328,729)
[1]	All common stock (except authorized shares), equity share, and per share amounts have been retroactively adjusted to reflect a one-for-four reverse stock split, which was effective June 7, 2017.
[2]	During the quarter ended September 30, 2017, the Company dissolved the NoranTel legal entity, which triggered a one-time foreign currency gain with the reversal of a cumulative translation adjustment. See Note 1.

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2017		Dec. 31, 2016
Cash flows from operating activities:
Net income (loss)	$ 947		$ (15,385)
Reconciliation of net loss to net cash used in operating activities:
Depreciation and amortization	3,747		4,714
Impairment of Long-Lived Assets to be Disposed of	0		1,181
Stock-based compensation	988		1,346
Loss on sale of fixed assets	10		11
Restructuring	165		3,055
Deferred taxes	(697)		20
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax	(608)
Exchange rate loss (gain)	(20)		44
Changes in assets and liabilities:
Accounts receivable	1,025		5,098
Inventories	3,047		509
Prepaid expenses and other current assets	545		494
Other assets	80		(7)
Deferred revenue	(618)		686
Accounts payable and accrued expenses	(3,542)		(6,802)
Net cash provided by (used in) operating activities	5,069		(5,036)
Cash flows from investing activities:
Maturities of held-to-maturity short-term debt securities	0		12,621
Maturities of other short-term investments	474		0
Purchases of held-to-maturity short-term debt securities	0		(2,066)
Purchases of other short-term investments	(5,011)		0
Purchases of property and equipment	(261)		(527)
Net cash provided by (used in) investing activities	(4,798)		10,028
Cash flows from financing activities:
Purchases of treasury stock	(558)		(146)
Payment of contingent consideration	0		(175)
Net cash provided by (used in) financing activities	(558)		(321)
Gain (loss) of exchange rate changes on cash	1		2
Net increase (decrease) in cash and cash equivalents	(286)		4,673
Cash and cash equivalents, beginning of period	21,778		19,169
Cash and cash equivalents, end of period (1)	$ 21,492	[1]	$ 23,842
[1]	As of December 31, 2017, the Company has $4.5 million of short-term investments in addition to cash and cash equivalents.

Basis of Presentation (Notes)

Basis of Presentation (Notes)	9 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation Reverse Stock Split All common stock, equity, share and per share amounts in the financial statements and notes have been retroactively adjusted to reflect a one-for-four reverse stock split, which was effective June 7, 2017. Description of Business Westell Technologies, Inc. (the Company) is a holding company. Its wholly owned subsidiary, Westell, Inc., designs and distributes telecommunications products, which are sold primarily to major telephone companies. During the second quarter ended September 30, 2017, the Company dissolved Noran Tel, Inc. (NoranTel) a wholly owned subsidiary of Westell, Inc. NoranTel's operations have been fully incorporated into Westell, Inc. As a result of the wind-up of NoranTel, the Company recognized a one-time $0.6 million foreign currency translation gain, which is presented in Other income, net on the Condensed Consolidated Statements of Operations. Basis of Presentation and Reporting The accompanying Condensed Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries. The Condensed Consolidated Financial Statements have been prepared using generally accepted accounting principles (GAAP) in the United States for interim financial reporting, and consistent with the instructions of Form 10-Q and Article 10 of Regulation S-X and, accordingly, they do not include all of the information and footnotes required in the annual consolidated financial statements and accompanying footnotes. The Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended March 31, 2017 . All intercompany accounts and transactions have been eliminated in consolidation. In the opinion of management, the unaudited interim financial statements included herein reflect all adjustments, consisting of normal recurring adjustments, necessary to present fairly the Company’s condensed consolidated financial position and the results of operations, comprehensive income (loss) and cash flows at December 31, 2017 , and for all periods presented. The results of operations for the periods presented are not necessarily indicative of the results that may be expected for fiscal year 2018 . Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and that affect revenue and expenses during the periods reported. Estimates are used when accounting for the allowance for uncollectible accounts receivable, net realizable value of inventory, product warranty accrued, relative selling prices, stock-based compensation, intangible assets fair value, depreciation, income taxes, and contingencies, among other things. Actual results could differ from those estimates. U.S. Tax Reform See Note 8 , Income Taxes for a discussion of the impact of the recently enacted U.S. Tax Reform legislation. Recently Adopted Accounting Pronouncements In July 2015, the FASB issued ASU 2015-11, Simplifying the Measurement of Inventory (ASU 2015-11). The core principle of the guidance is that an entity should measure inventory at the "lower of cost and net realizable value" and options that currently exist for "market value" will be eliminated. The ASU defines net realizable value as the "estimated selling prices in the ordinary course of business, less reasonably predictable cost of completion, disposal, and transportation." The Company adopted ASU 2015-11 on April 1, 2017. The adoption of this ASU did not have a material impact to the Company's Consolidated Financial Statements or related disclosures. Recently Issued Accounting Pronouncements Not Yet Adopted In May 2017, the FASB issued ASU 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting (ASU 2017-09). ASU 2017-09 clarifies which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. The standard is effective for annual periods, and interim periods within those annual reporting periods, beginning after December 15, 2017, with early adoption permitted. The Company is currently evaluating the potential impact ASU 2017-09 will have on the Company's Consolidated Financial Statements. In October 2016, the FASB issued ASU 2016-16, Income Taxes: Intra-Entity Transfers of Assets Other Than Inventory (ASU 2016-16). ASU 2016-16 requires the recognition of current and deferred income taxes for intra-entity asset transfers when the transaction occurs. ASU 2016-16 is effective for annual periods, and interim periods within those annual reporting periods, beginning after December 15, 2017. Early adoption is permitted. ASU 2016-16 is effective for the Company in the first quarter of fiscal 2019, and the Company is currently in the process of evaluating the potential impact of adoption of this updated authoritative guidance on the Company's Consolidated Financial Statements. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flow (Topic 230) (ASU 2016-15). This update is intended to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. The update provides new guidance regarding the classification of debt prepayment or debt extinguishment costs, settlement of zero-coupon debt instruments, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies, distributions received from equity method investments, beneficial interests in securitized transactions, and separately identifiable cash flows and application of the predominance principle. This standard will be effective for financial statements issued by public companies for annual periods, and interim periods within those annual reporting periods, beginning after December 15, 2017. Early adoption of the standard is permitted. The standard will be applied in a retrospective approach for each period presented. The Company does not anticipate any immediate impact to the Company upon adoption of ASU 2016-15 as the Company currently does not have any debt. In February 2016, the FASB issued ASU 2016-02, Leases (ASU 2016-02). In September 2017, the FASB issued ASU 2017-13, Revenue Recognition (Topic 605), Revenue from Contracts with Customers (Topic 606), Leases (Topic 840), and Leases (Topic 842) (ASU 2017-13), which provides additional implementation guidance on the previously issued ASU 2016-02. ASU 2016-02 requires lessees to recognize leases on the balance sheet as a lease liability with a corresponding right-of-use asset for leases with a lease term of more than one year. ASU 2016-02 is effective for financial statements issued for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted. The new standard requires a modified retrospective transition for capital or operating leases existing at or entered into after the beginning of the earliest comparative period presented in the financial statements, but it does not require transition accounting for leases that expire prior to the date of initial application. The Company is currently evaluating the impact that ASU 2016-02 will have on the Company's Consolidated Financial Statements and related disclosures. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (ASU 2014-09), that outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. ASU 2014-09 is based on the principle that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to fulfill a contract. Entities have the option of using either a full retrospective or a modified retrospective approach for the adoption of the new standard. ASU 2014-09 is initially scheduled to become effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period; early adoption is not permitted. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606) — Deferral of the Effective Date (ASU 2015-14) , which defers the effective date of ASU 2014-09 for one year and permits early adoption as early as the original effective date of ASU 2014-09. The new revenue standard may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized as of the date of adoption. In 2016, the FASB issued additional guidance to clarify the implementation guidance (ASU 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations ; ASU 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing ; ASU 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients: and ASU 2016-20 (Topic 606) Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers . In September 2017, the FASB issued ASU 2017-13, Revenue Recognition (Topic 605), Revenue from Contracts with Customers (Topic 606), Leases (Topic 840), and Leases (Topic 842) . In November 2017, the FASB issued ASU 2017-14, Income Statement—Reporting Comprehensive Income (Topic 220), Revenue Recognition (Topic 605), and Revenue from Contracts with Customers (Topic 606) . These amendments provide additional clarification and implementation guidance on the previously issued ASU 2014-09. The Company commenced the assessment of ASU 2014-09 during the first quarter of fiscal year 2018 and developed a project plan to guide the implementation. This project plan includes analyzing the standard’s impact on the Company’s contract portfolio, comparing historical accounting policies and practices to the requirements of the new standard and identifying potential differences from applying the requirements of the new standard to its contracts. The Company will draft an updated accounting policy, evaluate new disclosure requirements and identify and implement appropriate changes to business processes, systems and controls to support recognition and disclosure under the new standard. The Company continues to evaluate the impact this new standard will have on the current contracts with customers. The Company expects to adopt this new standard effective April 1, 2018, using the modified retrospective method that may result in a cumulative effect adjustment as of the date of adoption. The Company expects to complete its analysis on the impact to its Consolidated Financial Statements prior to the first quarter of fiscal year 2019. The Company will continue to monitor additional changes, modifications, clarifications or interpretations related to this guidance and the impact it will have on the Company's Consolidated Financial Statements and related disclosures. Significant Accounting Policy Update Accounts Receivable and Allowance for Doubtful Accounts Trade accounts receivable are recorded at the invoiced amount less payment discounts and estimated allowance for doubtful accounts. The Company provides allowances for doubtful accounts related to accounts receivable for estimated losses resulting from the inability of its customers to make required payments. The Company takes into consideration the overall quality of the receivable portfolio along with specifically identified customer risks. In circumstances where the Company is aware of a specific customer’s inability to meet its financial obligations to the Company, the Company provides allowances for bad debts against amounts due to reduce the net realized receivable to the amount it reasonably believes will be collected. In certain of the Company’s contracts, contractual billings do not coincide with revenue recognized on the contract. Unbilled accounts receivable represent revenue recorded in excess of amounts billable pursuant to contract provisions and, generally, become billable at contractually specified dates. Unbilled amounts are expected to be collected within one year. As of December 31, 2017 there was $220,000 of unbilled accounts receivable on the Condensed Consolidated Balance Sheets presented in Accounts Receivable. There was no unbilled accounts receivable as of March 31, 2017.

Restructuring Charge (Notes)

Restructuring Charge (Notes)	9 Months Ended
	Dec. 31, 2017
Restructuring Charges [Abstract]
Restructuring Charge	Restructuring Charges In the nine months ended December 31, 2017 , the Company recorded a restructuring expense of $0.2 million related to employee termination costs that spanned all three segments (the 2018 restructuring). In the second quarter of fiscal year 2017, the Company approved a restructuring plan (the 2017 restructuring) , including discontinuing development of the ClearLink Distributed Antenna System (DAS), a general reduction of headcount that spanned all three segments, and consolidation of facilities in Manchester, NH and Aurora, IL. The Company recognized a restructuring expense of $0.5 million and $3.1 million in the three and nine months ended December 31, 2016. The 2017 restructuring costs totaled $3.2 million in the twelve months ended March 31, 2017 , inclusive of non-cash charges of approximately $1.2 million related to losses on leased facilities, $1.3 million of employee termination costs, and $0.7 million of other associated costs. In the nine months ended December 31, 2016, a $1.2 million impairment charge of fixed assets and $1.6 million of E&O expense for ClearLink DAS inventory and pipeline inventory, associated with the IBW segment was recognized. The planned restructuring was substantially completed by March 31, 2017. As of December 31, 2017 , $0.2 million of the restructuring costs, related to the office space from the 2017 restructuring, are unpaid and accrued on the Condensed Consolidated Balance Sheets presented in Accrued restructuring. As of March 31, 2017, $1.2 million and $63,000 of the restructuring costs, primarily related to the office space from the 2015 restructuring and 2017 restructuring, were unpaid and accrued on the Condensed Consolidated Balance Sheets presented in Accrued restructuring and Accrued restructuring non-current, respectively. The restructuring costs are expected to be paid in full by the first quarter of fiscal year 2019 concurrent with the termination date of the contractual lease in Manchester, NH. Total liability for restructuring charges and their utilization for the nine months ended December 31, 2017 , are summarized as follows: Nine months ended December 31, 2017 (in thousands) Employee-related Other costs Total Liability at beginning of period $ — $ 1,234 $ 1,234 Charged 165 — 165 Paid (165 ) (1,068 ) (1,233 ) Liability at end of period $ — $ 166 $ 166

Interim Segment Information (No

Interim Segment Information (Notes)	9 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Interim Segment Information	Interim Segment Information Segment information is presented in accordance with a “management approach", which designates the internal reporting used by the chief operating decision-maker (CODM) for making decisions and assessing performance as the source of the Company's reportable segments. Westell’s Chief Executive Officer is the CODM. The CODM continues to define segment profit as gross profit less research and development expenses. The accounting policies of the segments are the same as those for Westell Technologies, Inc. described in the summary of significant accounting policies included in the Company's Annual Report on Form 10-K for year ended March 31, 2017. The Company’s three reportable segments are as follows: In-Building Wireless (IBW) Segment The IBW segment solutions enable cellular coverage in stadiums, arenas, malls, buildings, and other indoor areas not served well or at all by the existing "macro" outdoor cellular network. For commercial service, the IBW segment solutions include distributed antenna systems (DAS) conditioners and digital repeaters. For the public safety market, the IBW segment solutions include half-watt and two-watt repeaters and a battery backup unit. The Company’s IBW segment also offers ancillary products that consist of passive system components and antennas for both the commercial and public safety markets. Intelligent Site Management and Services (ISMS) Segment The ISMS segment solutions include a suite of remote units which provide machine-to-machine (M2M) communications that enable operators to remotely monitor, manage, and control site infrastructure and support systems. Remote units can be and often are combined with the Company’s Optima management software system. The Company also offers support agreement services (i.e., maintenance) and deployment services (i.e., installation). Communications Network Solutions (CNS) Segment The CNS segment solutions include a broad range of outdoor network infrastructure offerings consisting of integrated cabinets, power distribution products, copper and fiber connectivity panels, T1 network interface units (NIUs), and tower mounted amplifiers (TMAs). Segment information for the three and nine months ended December 31, 2017 , and 2016 , is set forth below: Three months ended December 31, 2017 (in thousands) IBW ISMS CNS Total Revenue $ 5,223 $ 5,802 $ 2,650 $ 13,675 Cost of revenue 2,754 2,642 2,203 7,599 Gross profit 2,469 3,160 447 6,076 Gross margin 47.3 % 54.5 % 16.9 % 44.4 % Research and development 750 547 245 1,542 Segment profit $ 1,719 $ 2,613 $ 202 4,534 Operating expenses: Sales and marketing 1,950 General and administrative 1,502 Intangible amortization 1,047 Operating profit (loss) 35 Other income, net 79 Income tax benefit (expense) 685 (1) Net income (loss) $ 799 Three months ended December 31, 2016 (in thousands) IBW ISMS CNS Total Revenue $ 6,224 $ 5,525 $ 3,234 $ 14,983 Cost of revenue 3,713 2,730 2,486 8,929 Gross profit 2,511 2,795 748 6,054 Gross margin 40.3 % 50.6 % 23.1 % 40.4 % Research and development 1,307 805 302 2,414 Segment profit $ 1,204 $ 1,990 $ 446 3,640 Operating expenses: Sales and marketing 1,943 General and administrative 1,777 Intangible amortization 1,212 Restructuring 490 Operating profit (loss) (1,782 ) Other income, net (15 ) Income tax benefit (expense) (10 ) Net income (loss) $ (1,807 ) (1) During the quarter ended December 31, 2017, the Company had income tax benefit from the release of the tax valuation allowance associated with previously generated alternative minimum tax (AMT) credits due to the enacted Tax Reform. See Note 8. Nine months ended December 31, 2017 (in thousands) IBW ISMS CNS Total Revenue $ 20,098 $ 14,662 $ 12,721 $ 47,481 Cost of revenue 10,965 7,157 9,241 27,363 Gross profit 9,133 7,505 3,480 20,118 Gross margin 45.4 % 51.2 % 27.4 % 42.4 % Research and development 3,656 1,635 732 6,023 Segment profit $ 5,477 $ 5,870 $ 2,748 14,095 Operating expenses: Sales and marketing 6,278 General and administrative 5,022 Intangible amortization 3,142 Restructuring 165 Operating profit (loss) (512 ) Other income, net 799 (2) Income tax benefit (expense) 660 (1) Net income (loss) $ 947 Nine months ended December 31, 2016 (in thousands) IBW ISMS CNS Total Revenue $ 18,989 $ 14,773 $ 13,817 $ 47,579 Cost of revenue 13,251 7,552 9,790 30,593 (3) Gross profit 5,738 7,221 4,027 16,986 (3) Gross margin 30.2 % 48.9 % 29.1 % 35.7 % (3) Research and development 5,265 3,336 1,417 10,018 Segment profit (loss) $ 473 $ 3,885 $ 2,610 6,968 Operating expenses: Sales and marketing 8,220 General and administrative 6,340 Intangible amortization 3,613 Restructuring 3,055 Long-lived assets impairment 1,181 Operating profit (loss) (15,441 ) Other income, net 76 Income tax benefit (expense) (20 ) Net income (loss) $ (15,385 ) (1) During the quarter ended December 31, 2017, the Company had income tax benefit from the release of the tax valuation allowance associated with previously generated alternative minimum tax (AMT) credits due to the enacted Tax Reform. See Note 8. (2) During the quarter ended September 30, 2017, the Company dissolved the NoranTel legal entity, which triggered a one-time foreign currency gain with the reversal of a cumulative translation adjustment. See Note 1. (3) The nine months ended December 31, 2016, includes E&O expense for ClearLink DAS inventory and pipeline inventory. See Note 2 . Segment asset information is not reported to or used by the CODM.	[1]
[1]	The nine months ended December 31, 2016, includes $1.6 million of E&O expense for ClearLink DAS inventory and pipeline inventory.

Inventories (Notes)

Inventories (Notes)	9 Months Ended
	Dec. 31, 2017
Inventory, Net [Abstract]
Inventories	Inventories Inventories are stated at the lower of first-in, first-out cost or market value. The components of inventories are as follows: (in thousands) December 31, 2017 March 31, 2017 Raw materials $ 3,148 $ 3,871 Finished goods 6,316 8,640 Total inventories $ 9,464 $ 12,511

Stock-Based Compensation (Notes

Stock-Based Compensation (Notes)	9 Months Ended
	Dec. 31, 2017
Share-based Compensation [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Westell Technologies, Inc. 2015 Omnibus Incentive Compensation Plan (the 2015 Plan) was approved at the annual meeting of stockholders on September 16, 2015. The 2015 Plan replaced the Westell Technologies, Inc. 2004 Stock Incentive Plan (the 2004 Plan). If any award granted under the 2015 Plan or the 2004 Plan is canceled, terminates, expires, or lapses for any reason, any Shares subject to such award shall again be available for the grant of an award under the 2015 Plan. Shares subject to an award shall not again be made available for issuance under the Plan if such Shares are: (a) shares delivered to or withheld by the Company to pay the grant or purchase price of an award, or (b) shares delivered to or withheld by the Company to pay the withholding taxes related to an award. The stock options, restricted stock awards, and restricted stock units (RSUs) awarded under the 2015 Plan generally vest in equal annual installments over 3 years for employees and 1 year for independent directors. The stock options, restricted stock awards, and RSUs awarded under the 2004 Plan vest in equal annual installments over 4 years . Performance stock units (PSUs) earned vest over the performance period. Certain awards provide for accelerated vesting if there is a change in control (as defined in the 2015 Plan), or when provided within individual employment contracts. The Company accounts for forfeitures as they occur. The Company issues new shares for stock awards under the 2015 Plan. The following table is a summary of total stock-based compensation expense resulting from stock options, restricted stock, RSUs and PSUs, during the three and nine months ended December 31, 2017 , and 2016 : Three months ended December 31, Nine months ended December 31, (in thousands) 2017 2016 2017 2016 Stock-based compensation expense $ 316 $ 253 $ 988 $ 1,346 Income tax benefit — — — — Total stock-based compensation expense, after taxes $ 316 $ 253 $ 988 $ 1,346 Stock Options Stock option activity for the nine months ended December 31, 2017 , is as follows: Shares Weighted-Average Exercise Price Per Share Weighted-Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (1) (in thousands) Outstanding on March 31, 2017 362,396 $ 4.89 5.4 $ 39 Granted 100,000 3.06 Exercised — — Forfeited (199,483 ) 3.72 Expired (61,018 ) 5.82 Outstanding on December 31, 2017 201,895 $ 4.86 4.6 $ 76 (1) The intrinsic value for the stock options is calculated based on the difference between the exercise price of the underlying awards and the Westell Technologies’ closing stock price as of the respective reporting date. Restricted Stock The following table sets forth restricted stock activity for the nine months ended December 31, 2017 : Shares Weighted-Average Grant Date Fair Value Non-vested as of March 31, 2017 34,375 $ 4.11 Granted 104,636 3.01 Vested (66,250 ) 3.30 Forfeited — — Non-vested as of December 31, 2017 72,761 $ 3.26 RSUs The following table sets forth the RSU activity for the nine months ended December 31, 2017 : Shares Weighted-Average Grant Date Fair Value Non-vested as of March 31, 2017 373,886 $ 4.48 Granted 552,000 2.89 Vested (137,162 ) 5.05 Forfeited (239,193 ) 3.64 Non-vested as of December 31, 2017 549,531 $ 3.11 PSUs The following table sets forth the PSU activity for the nine months ended December 31, 2017 : Shares Weighted-Average Grant Date Fair Value Non-vested as of March 31, 2017 (at target) 76,053 $ 3.56 Granted, at target 40,000 3.06 Vested (49,686 ) 2.30 Forfeited (58,867 ) 2.79 Non-vested as of December 31, 2017 (at target) 7,500 $ 15.30

Product Warranties (Notes)

Product Warranties (Notes)	9 Months Ended
	Dec. 31, 2017
Product Warranties Disclosures [Abstract]
Product Warranties	Product Warranties The Company’s products carry a limited warranty ranging from one to five years for the products within the IBW segment, typically one year for products within the ISMS segment, and one to seven years for products within the CNS segment. The specific terms and conditions of those warranties vary depending upon the customer and the products sold. Factors that affect the estimate of the Company’s warranty reserve include: the number of units shipped, anticipated rates of warranty claims, and cost per claim. The Company periodically assesses the adequacy of its recorded warranty liability and adjusts the reserve as necessary. The current portions of the warranty reserve are $162,000 and $163,000 as of December 31, 2017 , and March 31, 2017 , respectively, and are presented on the Condensed Consolidated Balance Sheets in Accrued expenses. The non-current portions of the warranty reserves are $287,000 and $232,000 as of December 31, 2017 , and March 31, 2017 , respectively, and are presented on the Condensed Consolidated Balance Sheets in Other non-current liabilities. The following table presents the changes in the Company’s product warranty reserve: Three months ended December 31, Nine months ended December 31, (in thousands) 2017 2016 2017 2016 Total product warranty reserve at the beginning of the period $ 446 $ 460 $ 395 $ 436 Warranty expense to cost of revenue 42 12 160 80 Utilization (39 ) (2 ) (106 ) (46 ) Total product warranty reserve at the end of the period $ 449 $ 470 $ 449 $ 470

Variable Interest Entity and Gu

Variable Interest Entity and Guarantee (Notes)	9 Months Ended
	Dec. 31, 2017
Guarantees [Abstract]
Equity Method Investment [Text Block]	Variable Interest Entity and Guarantee The Company has a 50% equity ownership in AccessTel Kentrox Australia PTY LTD (AKA). AKA distributes network management solutions provided by the Company and the other 50% owner to one customer. The Company holds equal voting control with the other owner. All actions of AKA are decided at the board level by majority vote. The Company evaluated ASC 810, Consolidations , and concluded that AKA is a variable interest entity (VIE) and the Company has a variable interest in the VIE. The Company has concluded that it is not the primary beneficiary of AKA and, therefore, consolidation is not required. As of December 31, 2017 , and March 31, 2017 , the carrying amount of the Company's investment in AKA was approximately $61,000 and $111,000 , respectively, which is presented on the Condensed Consolidated Balance Sheets within Other non-current assets. The Company received a cash dividend payment of $59,000 from AKA during the three months ended September 30, 2017. The Company's revenue from sales to AKA for the three months ended December 31, 2017 , and 2016 , was $1.5 million and $0.3 million , respectively. The Company's revenue from sales to AKA for the nine months ended December 31, 2017 and 2016 , was $3.2 million and $2.0 million , respectively. Accounts receivable from AKA was $1.0 million and $0.5 million as of December 31, 2017 , and March 31, 2017 , respectively. Deferred revenue, which primarily relates to AKA maintenance contracts, was $1.5 million and $2.8 million as of December 31, 2017 , and March 31, 2017 , respectively. The Company also has provided an unlimited guarantee for the performance of the other 50% owner in AKA, which primarily provides support and engineering services to the customer. This guarantee was put in place at the request of the AKA customer. The guarantee, which is estimated to have a maximum potential future payment of $0.7 million , will stay in place as long as the contract between AKA and the customer is in place. The Company would have recourse against the other 50% owner in AKA in the event the guarantee is triggered. The Company determined that it could perform on the obligation it guaranteed at a positive rate of return and, therefore, did not assign value to the guarantee. The Company's exposure to loss as a result of its involvement with AKA, exclusive of lost profits, is limited to the items noted above.

Income Taxes (Notes)

Income Taxes (Notes)	9 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes At the end of each interim period, the Company makes its best estimate of the effective tax rate expected to be applicable for the full fiscal year and uses that rate to provide for income taxes on a current year-to-date basis before discrete items. If a reliable estimate cannot be made, the Company may make a reasonable estimate of the annual effective tax rate, including use of the actual effective rate for the year-to-date. The impact of discrete items is recorded in the quarter in which they occur. The Company utilizes the liability method of accounting for income taxes and deferred taxes, which are determined based on the differences between the financial statements and tax basis of assets and liabilities given the enacted tax laws. The Company evaluates the need for valuation allowances on the net deferred tax assets under the rules of ASC 740, Income Taxes. In assessing the realizability of the Company's deferred tax assets, the Company considers whether it is more likely than not that some or all of the deferred tax assets will be realized through the generation of future taxable income. In making this determination, the Company assessed all of the evidence available at the time, including recent earnings, forecasted income projections and historical performance. The Company determined that the negative evidence outweighed the objectively verifiable positive evidence and previously recorded a full valuation allowance against deferred tax assets. The Company will continue to reassess realizability going forward. On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (the “Act”). The Act significantly revises the future ongoing U.S. corporate income tax by, among other things, lowering the U.S. corporate federal income tax rate from 34% to 21% effective January 1, 2018. As a result, a blended federal rate of 30.75% is required for the current year income tax expense. Further, the Company is required to re-measure, through income tax expense, its deferred tax assets and liabilities using the enacted rate at which the items are expected to be recovered or settled. During the third quarter, the Company recorded provisional amounts as a result of the re-measurement of the Company’s net deferred tax asset did not result in income tax expense due to the Company’s full valuation allowance position. Total net deferred tax assets decreased by $14.3 million , which includes a reclassification of the federal alternative minimum tax (“AMT”) credit to long term receivable, discussed below. As of December 31, 2017 , the Company had net deferred tax assets of approximately $38.6 million before a valuation allowance of $38.6 million . The final transition impacts of the Act may differ from the above estimate, possibly materially, due to, among other things, changes in interpretations of the Act, any legislative action to address questions that arise because of the Act, any changes in accounting standards for income taxes or related interpretations in response to the Act, or any updates or changes to estimates the Company has utilized to calculate the transition impacts, including impacts from changes to current year earnings estimates. The Securities Exchange Commission has issued guidance that allows for a measurement period of up to one year after the enactment date of the Act to finalize the recording of the related tax impacts. We currently anticipate finalizing and recording any resulting adjustments in our Form 10-K for our current fiscal year ending March 31, 2018. As of December 31, 2017, the Company has $697,000 of AMT credit carryforward, which does not expire and is now carried as a tax receivable since, under new federal tax law, the Company expects to recover the entire amount by 2022 via a tax refund. Previously, there was a valuation allowance against the entire AMT credit carryforward. In the third quarter, the Company is reversing the portion of the valuation allowance related to the AMT credit carryforward, resulting in a discrete tax benefit of $697,000 . The Company recorded $685,000 and $660,000 of income tax benefit in the three and nine months ended December 31, 2017 , respectively, using an effective income tax rate of 1.76% plus discrete items including the AMT tax benefit described above. The Company recorded $10,000 and $20,000 of income tax expense in the three and nine months ended December 31, 2016 , respectively, using an effective rate of (0.13)% plus discrete items. The effective rate in both periods is impacted by the intraperiod allocation as a result of income or loss from continuing operations, and states which base tax on gross margin and not pretax income.

Commitments and Contingencies (

Commitments and Contingencies (Notes)	9 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Litigation and Contingency Reserves The Company and its subsidiaries are involved in various assertions, claims, proceedings and requests for indemnification concerning intellectual property, including patent infringement suits involving technologies that may be incorporated in the Company’s products, which are being handled and defended in the ordinary course of business. These matters are in various stages of investigation and litigation, and they are being vigorously defended. Although the Company does not expect that the outcome in any of these matters, individually or collectively, will have a material adverse effect on its financial condition or results of operations, litigation is inherently unpredictable. Therefore, judgments could be rendered, or settlements entered, that could adversely affect the Company’s operating results or cash flows in a particular period. The Company routinely assesses all of its litigation and threatened litigation as to the probability of ultimately incurring a liability, and it records its best estimate of the ultimate loss in situations where it assesses the likelihood of loss as probable. As of December 31, 2017 , and March 31, 2017 , the Company has not recorded any contingent liability attributable to existing litigation. In the ordinary course of operations, the Company receives claims where the Company believes an unfavorable outcome is possible and/or for which is probable and no estimate of possible losses can currently be made. A significant customer was a defendant in patent infringement claims and is asserting possible indemnity rights under contracts with the Company. The customer has settled one matter, which has been dismissed, and won summary judgment of all claims in the other. The customer has informed the Company that the customer intends to seek to recover from the Company a share of the settlement and defense costs. The Company has not been involved in any settlement discussions nor informed by the customer of any settlement details and therefore management is currently unable to estimate a range of potential loss associated with this claim with any degree of certainty, and the Company is not yet able to calculate the exposure to this claim, which will vary depending upon the settlement reached by the customer and the Company's contribution ratio.

Short-term Investments (Notes)

Short-term Investments (Notes)	9 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Short Term Investments [Text Block]	Short-term Investments As of December 31, 2017 , the Company owned Certificates of Deposit amounting to $4.5 million held at cost. There were no short-term investments as of March 31, 2017 .

Fair Value Measurements (Notes)

Fair Value Measurements (Notes)	9 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair value is defined by ASC 820, Fair Value Measurements and Disclosures (ASC 820) , as the price that would be received upon selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. ASC 820 establishes a three-level fair value hierarchy that prioritizes the inputs used to measure fair value. The hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: • Level 1 – Quoted prices in active markets for identical assets and liabilities. • Level 2 – Quoted prices in active markets for similar assets and liabilities, or other inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument. • Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets and liabilities. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. The Company’s money market funds are measured using Level 1 inputs. The following table presents available-for-sale securities measured at fair value on a recurring basis as of December 31, 2017 : (in thousands) Total Fair Value Quoted Prices in Significant Other Significant Balance Sheet Assets: Money market funds $ 12,724 $ 12,724 — — Cash and cash The following table presents available-for-sale securities measured at fair value on a recurring basis as of March 31, 2017 : (in thousands) Total Fair Value Quoted Prices in Significant Other Significant Balance Sheet Assets: Money market funds $ 17,162 $ 17,162 — — Cash and cash The fair value of the money market funds approximates their carrying amounts due to the short-term nature of these financial assets.

Share Repurchases (Notes)

Share Repurchases (Notes)	9 Months Ended
	Dec. 31, 2017
Payments for Repurchase of Equity [Abstract]
Share Repurchases	Share Repurchases In May 2017, the Board of Directors authorized a new share repurchase program whereby the Company may repurchase up to an aggregate of $2.0 million of its outstanding Class A Common Stock (the 2017 authorization). The 2017 authorization is in addition to the $0.1 million that was remaining from the August 2011 $20.0 million authorization (the 2011 authorization). There were 133,608 shares repurchased under the 2011 and 2017 authorizations during the nine months ended December 31, 2017 at a weighted average purchase price of $2.98 per share. There were no shares repurchased under the 2011 authorization during the nine months ended December 31, 2016. There was approximately $1.7 million remaining for additional share repurchases under the 2017 authorization as of December 31, 2017 . Additionally, in the nine months ended December 31, 2017, and December 31, 2016, the Company repurchased 54,572 and 44,005 shares of Class A Common Stock, respectively, from certain employees that were surrendered to satisfy the minimum statutory tax withholding obligations on the vesting of restricted stock, RSUs and PSUs. These repurchases were not included in the authorized share repurchase programs and had a weighted-average purchase price of $2.89 and $3.32 per share, respectively.

Intangibles Assets (Notes)

Intangibles Assets (Notes)	9 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets Disclosure [Text Block]	Intangible Assets Intangible assets include customer relationships, trade names, developed technology and other intangibles. Intangible assets with determinable lives are amortized over their estimated useful lives. Intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Determination of recoverability is based on an estimate of undiscounted future cash flows resulting from the use of the asset and its eventual disposition. If the carrying amount of an asset exceeds its estimated future undiscounted cash flows, an impairment loss is recorded for the excess of the asset’s carrying amount over its fair value. Intangible asset impairment charges are presented in Intangible amortization on the Condensed Consolidated Statements of Operations. As a result of the Company reorganizing its reporting structure in the first quarter of fiscal year 2017, the Company reassigned assets and liabilities to reporting units. During the third quarter of fiscal year 2017, the Company experienced triggering events that resulted in the Company testing its intangible assets for impairment. In evaluating whether it is more likely than not that the fair value of the Company's reporting units were less than their carrying value, the Company assessed all relevant events and circumstances and determined that, due to the overall financial performance of the Company and recent change in reporting structure, indicators of impairment were present. The Company performed an evaluation to test IBW, ISMS and CNS intangible assets for recoverability and concluded there was no impairment during the nine months ended December 31, 2016, for the IBW and ISMS the reporting units. During the third quarter of fiscal 2017, CNS revenue declined more than previously forecasted. As a result, the CNS reporting unit did not pass the recoverability test, therefore the Company completed the second step of the evaluation, which compares the implied fair value of the intangible assets as determined using the multiple-period excess earnings method and the distributor model, with the carrying value to determine the amount of the impairment loss. As a result of that impairment evaluation, the Company concluded that the customer list acquired from the previous ANTONE acquisition for its TMA products was impaired and recorded an impairment charge of $31,000 during the quarter ended December 31, 2016. There was no intangible asset impairment during the nine months ended December 31, 2017 , for the IBW, ISMS and CNS reporting units.

Accrued Liabilities (Notes)

Accrued Liabilities (Notes)	9 Months Ended
	Dec. 31, 2017
Schedule of Accrued Liabilities [Table Text Block]	Accrued Expenses The components of accrued expenses are as follows: (in thousands) December 31, 2017 March 31, 2017 Accrued compensation $ 731 $ 1,256 Accrued contractual obligation 1,445 1,445 Other accrued expenses 1,352 1,572 Total accrued expenses $ 3,528 $ 4,273

Land Property and Equipment (No

Land Property and Equipment (Notes)	9 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment Disclosure [Text Block]	Land, Property, and Equipment Long-lived assets consist of property and equipment. Long-lived assets that are held and used should be reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the long-lived assets might not be recoverable. Due to a significant adverse change in the business climate connected to the ClearLink DAS development project, the Company determined indicators of impairment were present as of June 30, 2016. The Company determined that equipment related to development and manufacturing of this product was fully impaired and recorded an impairment charge of $1.2 million in the nine months ended December 31, 2016. Long-lived asset impairment charges are presented in Long-lived assets impairment on the Condensed Consolidated Statements of Operations. See Note 2 Restructuring Charges . There was no long-lived asset impairment during the nine months ended December 31, 2017 . The components of fixed assets are as follows: (in thousands) December 31, 2017 March 31, 2017 Land $ 672 $ 672 Machinery and equipment 1,603 1,698 Office, computer and research equipment 5,473 6,012 Leasehold improvements 1,275 7,680 Land, property and equipment, gross $ 9,023 $ 16,062 Less accumulated depreciation and amortization (7,393 ) (14,078 ) Land, property and equipment, net $ 1,630 $ 1,984 The significant decrease in the gross fixed assets and accumulated depreciation is primarily related to the disposals of fully depreciated leasehold improvements associated with a building operating lease that ended on September 30, 2017.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed consolidated financial statements	The accompanying Condensed Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries. The Condensed Consolidated Financial Statements have been prepared using generally accepted accounting principles (GAAP) in the United States for interim financial reporting, and consistent with the instructions of Form 10-Q and Article 10 of Regulation S-X and, accordingly, they do not include all of the information and footnotes required in the annual consolidated financial statements and accompanying footnotes. The Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended March 31, 2017 . All intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and that affect revenue and expenses during the periods reported. Estimates are used when accounting for the allowance for uncollectible accounts receivable, net realizable value of inventory, product warranty accrued, relative selling prices, stock-based compensation, intangible assets fair value, depreciation, income taxes, and contingencies, among other things. Actual results could differ from those estimates.
New Accounting Pronouncements	Recently Adopted Accounting Pronouncements In July 2015, the FASB issued ASU 2015-11, Simplifying the Measurement of Inventory (ASU 2015-11). The core principle of the guidance is that an entity should measure inventory at the "lower of cost and net realizable value" and options that currently exist for "market value" will be eliminated. The ASU defines net realizable value as the "estimated selling prices in the ordinary course of business, less reasonably predictable cost of completion, disposal, and transportation." The Company adopted ASU 2015-11 on April 1, 2017. The adoption of this ASU did not have a material impact to the Company's Consolidated Financial Statements or related disclosures. Recently Issued Accounting Pronouncements Not Yet Adopted In May 2017, the FASB issued ASU 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting (ASU 2017-09). ASU 2017-09 clarifies which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. The standard is effective for annual periods, and interim periods within those annual reporting periods, beginning after December 15, 2017, with early adoption permitted. The Company is currently evaluating the potential impact ASU 2017-09 will have on the Company's Consolidated Financial Statements. In October 2016, the FASB issued ASU 2016-16, Income Taxes: Intra-Entity Transfers of Assets Other Than Inventory (ASU 2016-16). ASU 2016-16 requires the recognition of current and deferred income taxes for intra-entity asset transfers when the transaction occurs. ASU 2016-16 is effective for annual periods, and interim periods within those annual reporting periods, beginning after December 15, 2017. Early adoption is permitted. ASU 2016-16 is effective for the Company in the first quarter of fiscal 2019, and the Company is currently in the process of evaluating the potential impact of adoption of this updated authoritative guidance on the Company's Consolidated Financial Statements. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flow (Topic 230) (ASU 2016-15). This update is intended to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. The update provides new guidance regarding the classification of debt prepayment or debt extinguishment costs, settlement of zero-coupon debt instruments, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies, distributions received from equity method investments, beneficial interests in securitized transactions, and separately identifiable cash flows and application of the predominance principle. This standard will be effective for financial statements issued by public companies for annual periods, and interim periods within those annual reporting periods, beginning after December 15, 2017. Early adoption of the standard is permitted. The standard will be applied in a retrospective approach for each period presented. The Company does not anticipate any immediate impact to the Company upon adoption of ASU 2016-15 as the Company currently does not have any debt. In February 2016, the FASB issued ASU 2016-02, Leases (ASU 2016-02). In September 2017, the FASB issued ASU 2017-13, Revenue Recognition (Topic 605), Revenue from Contracts with Customers (Topic 606), Leases (Topic 840), and Leases (Topic 842) (ASU 2017-13), which provides additional implementation guidance on the previously issued ASU 2016-02. ASU 2016-02 requires lessees to recognize leases on the balance sheet as a lease liability with a corresponding right-of-use asset for leases with a lease term of more than one year. ASU 2016-02 is effective for financial statements issued for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted. The new standard requires a modified retrospective transition for capital or operating leases existing at or entered into after the beginning of the earliest comparative period presented in the financial statements, but it does not require transition accounting for leases that expire prior to the date of initial application. The Company is currently evaluating the impact that ASU 2016-02 will have on the Company's Consolidated Financial Statements and related disclosures. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (ASU 2014-09), that outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. ASU 2014-09 is based on the principle that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to fulfill a contract. Entities have the option of using either a full retrospective or a modified retrospective approach for the adoption of the new standard. ASU 2014-09 is initially scheduled to become effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period; early adoption is not permitted. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606) — Deferral of the Effective Date (ASU 2015-14) , which defers the effective date of ASU 2014-09 for one year and permits early adoption as early as the original effective date of ASU 2014-09. The new revenue standard may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized as of the date of adoption. In 2016, the FASB issued additional guidance to clarify the implementation guidance (ASU 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations ; ASU 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing ; ASU 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients: and ASU 2016-20 (Topic 606) Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers . In September 2017, the FASB issued ASU 2017-13, Revenue Recognition (Topic 605), Revenue from Contracts with Customers (Topic 606), Leases (Topic 840), and Leases (Topic 842) . In November 2017, the FASB issued ASU 2017-14, Income Statement—Reporting Comprehensive Income (Topic 220), Revenue Recognition (Topic 605), and Revenue from Contracts with Customers (Topic 606) . These amendments provide additional clarification and implementation guidance on the previously issued ASU 2014-09. The Company commenced the assessment of ASU 2014-09 during the first quarter of fiscal year 2018 and developed a project plan to guide the implementation. This project plan includes analyzing the standard’s impact on the Company’s contract portfolio, comparing historical accounting policies and practices to the requirements of the new standard and identifying potential differences from applying the requirements of the new standard to its contracts. The Company will draft an updated accounting policy, evaluate new disclosure requirements and identify and implement appropriate changes to business processes, systems and controls to support recognition and disclosure under the new standard. The Company continues to evaluate the impact this new standard will have on the current contracts with customers. The Company expects to adopt this new standard effective April 1, 2018, using the modified retrospective method that may result in a cumulative effect adjustment as of the date of adoption. The Company expects to complete its analysis on the impact to its Consolidated Financial Statements prior to the first quarter of fiscal year 2019. The Company will continue to monitor additional changes, modifications, clarifications or interpretations related to this guidance and the impact it will have on the Company's Consolidated Financial Statements and related disclosures.
Trade and Other Accounts Receivable, Unbilled Receivables, Policy [Policy Text Block]	In certain of the Company’s contracts, contractual billings do not coincide with revenue recognized on the contract. Unbilled accounts receivable represent revenue recorded in excess of amounts billable pursuant to contract provisions and, generally, become billable at contractually specified dates. Unbilled amounts are expected to be collected within one year.
Inventory	Inventories are stated at the lower of first-in, first-out cost or market value.
Fair Value Measurement	Fair value is defined by ASC 820, Fair Value Measurements and Disclosures (ASC 820) , as the price that would be received upon selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. ASC 820 establishes a three-level fair value hierarchy that prioritizes the inputs used to measure fair value. The hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: • Level 1 – Quoted prices in active markets for identical assets and liabilities. • Level 2 – Quoted prices in active markets for similar assets and liabilities, or other inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument. • Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets and liabilities. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs.

Restructuring Charge (Tables)

Restructuring Charge (Tables)	9 Months Ended
	Dec. 31, 2017
Restructuring Charges [Abstract]
Restructuring charges	Total liability for restructuring charges and their utilization for the nine months ended December 31, 2017 , are summarized as follows: Nine months ended December 31, 2017 (in thousands) Employee-related Other costs Total Liability at beginning of period $ — $ 1,234 $ 1,234 Charged 165 — 165 Paid (165 ) (1,068 ) (1,233 ) Liability at end of period $ — $ 166 $ 166

Interim Segment Information (Ta

Interim Segment Information (Tables)	9 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment information	Segment information for the three and nine months ended December 31, 2017 , and 2016 , is set forth below: Three months ended December 31, 2017 (in thousands) IBW ISMS CNS Total Revenue $ 5,223 $ 5,802 $ 2,650 $ 13,675 Cost of revenue 2,754 2,642 2,203 7,599 Gross profit 2,469 3,160 447 6,076 Gross margin 47.3 % 54.5 % 16.9 % 44.4 % Research and development 750 547 245 1,542 Segment profit $ 1,719 $ 2,613 $ 202 4,534 Operating expenses: Sales and marketing 1,950 General and administrative 1,502 Intangible amortization 1,047 Operating profit (loss) 35 Other income, net 79 Income tax benefit (expense) 685 (1) Net income (loss) $ 799 Three months ended December 31, 2016 (in thousands) IBW ISMS CNS Total Revenue $ 6,224 $ 5,525 $ 3,234 $ 14,983 Cost of revenue 3,713 2,730 2,486 8,929 Gross profit 2,511 2,795 748 6,054 Gross margin 40.3 % 50.6 % 23.1 % 40.4 % Research and development 1,307 805 302 2,414 Segment profit $ 1,204 $ 1,990 $ 446 3,640 Operating expenses: Sales and marketing 1,943 General and administrative 1,777 Intangible amortization 1,212 Restructuring 490 Operating profit (loss) (1,782 ) Other income, net (15 ) Income tax benefit (expense) (10 ) Net income (loss) $ (1,807 ) (1) During the quarter ended December 31, 2017, the Company had income tax benefit from the release of the tax valuation allowance associated with previously generated alternative minimum tax (AMT) credits due to the enacted Tax Reform. See Note 8. Nine months ended December 31, 2017 (in thousands) IBW ISMS CNS Total Revenue $ 20,098 $ 14,662 $ 12,721 $ 47,481 Cost of revenue 10,965 7,157 9,241 27,363 Gross profit 9,133 7,505 3,480 20,118 Gross margin 45.4 % 51.2 % 27.4 % 42.4 % Research and development 3,656 1,635 732 6,023 Segment profit $ 5,477 $ 5,870 $ 2,748 14,095 Operating expenses: Sales and marketing 6,278 General and administrative 5,022 Intangible amortization 3,142 Restructuring 165 Operating profit (loss) (512 ) Other income, net 799 (2) Income tax benefit (expense) 660 (1) Net income (loss) $ 947 Nine months ended December 31, 2016 (in thousands) IBW ISMS CNS Total Revenue $ 18,989 $ 14,773 $ 13,817 $ 47,579 Cost of revenue 13,251 7,552 9,790 30,593 (3) Gross profit 5,738 7,221 4,027 16,986 (3) Gross margin 30.2 % 48.9 % 29.1 % 35.7 % (3) Research and development 5,265 3,336 1,417 10,018 Segment profit (loss) $ 473 $ 3,885 $ 2,610 6,968 Operating expenses: Sales and marketing 8,220 General and administrative 6,340 Intangible amortization 3,613 Restructuring 3,055 Long-lived assets impairment 1,181 Operating profit (loss) (15,441 ) Other income, net 76 Income tax benefit (expense) (20 ) Net income (loss) $ (15,385 ) (1)

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Dec. 31, 2017
Inventory, Net [Abstract]
Components of inventories	The components of inventories are as follows: (in thousands) December 31, 2017 March 31, 2017 Raw materials $ 3,148 $ 3,871 Finished goods 6,316 8,640 Total inventories $ 9,464 $ 12,511

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Dec. 31, 2017
Share-based Compensation [Abstract]
Stock-based compensation expense	The following table is a summary of total stock-based compensation expense resulting from stock options, restricted stock, RSUs and PSUs, during the three and nine months ended December 31, 2017 , and 2016 : Three months ended December 31, Nine months ended December 31, (in thousands) 2017 2016 2017 2016 Stock-based compensation expense $ 316 $ 253 $ 988 $ 1,346 Income tax benefit — — — — Total stock-based compensation expense, after taxes $ 316 $ 253 $ 988 $ 1,346
Stock option activity	Stock option activity for the nine months ended December 31, 2017 , is as follows: Shares Weighted-Average Exercise Price Per Share Weighted-Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (1) (in thousands) Outstanding on March 31, 2017 362,396 $ 4.89 5.4 $ 39 Granted 100,000 3.06 Exercised — — Forfeited (199,483 ) 3.72 Expired (61,018 ) 5.82 Outstanding on December 31, 2017 201,895 $ 4.86 4.6 $ 76 (1) The intrinsic value for the stock options is calculated based on the difference between the exercise price of the underlying awards and the Westell Technologies’ closing stock price as of the respective reporting date
Restricted stock activity	Restricted Stock The following table sets forth restricted stock activity for the nine months ended December 31, 2017 : Shares Weighted-Average Grant Date Fair Value Non-vested as of March 31, 2017 34,375 $ 4.11 Granted 104,636 3.01 Vested (66,250 ) 3.30 Forfeited — — Non-vested as of December 31, 2017 72,761 $ 3.26 RSUs The following table sets forth the RSU activity for the nine months ended December 31, 2017 : Shares Weighted-Average Grant Date Fair Value Non-vested as of March 31, 2017 373,886 $ 4.48 Granted 552,000 2.89 Vested (137,162 ) 5.05 Forfeited (239,193 ) 3.64 Non-vested as of December 31, 2017 549,531 $ 3.11 PSUs The following table sets forth the PSU activity for the nine months ended December 31, 2017 : Shares Weighted-Average Grant Date Fair Value Non-vested as of March 31, 2017 (at target) 76,053 $ 3.56 Granted, at target 40,000 3.06 Vested (49,686 ) 2.30 Forfeited (58,867 ) 2.79 Non-vested as of December 31, 2017 (at target) 7,500 $ 15.30

Product Warranties (Tables)

Product Warranties (Tables)	9 Months Ended
	Dec. 31, 2017
Product Warranties Disclosures [Abstract]
Changes in Company's product warranty reserve	The following table presents the changes in the Company’s product warranty reserve: Three months ended December 31, Nine months ended December 31, (in thousands) 2017 2016 2017 2016 Total product warranty reserve at the beginning of the period $ 446 $ 460 $ 395 $ 436 Warranty expense to cost of revenue 42 12 160 80 Utilization (39 ) (2 ) (106 ) (46 ) Total product warranty reserve at the end of the period $ 449 $ 470 $ 449 $ 470

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Assets and liabilities measured at fair value on a recurring basis and their related valuation inputs	The following table presents available-for-sale securities measured at fair value on a recurring basis as of December 31, 2017 : (in thousands) Total Fair Value Quoted Prices in Significant Other Significant Balance Sheet Assets: Money market funds $ 12,724 $ 12,724 — — Cash and cash The following table presents available-for-sale securities measured at fair value on a recurring basis as of March 31, 2017 : (in thousands) Total Fair Value Quoted Prices in Significant Other Significant Balance Sheet Assets: Money market funds $ 17,162 $ 17,162 — — Cash and cash

Land Property and Equipment (Ta

Land Property and Equipment (Tables)	9 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment [Table Text Block]	The components of fixed assets are as follows: (in thousands) December 31, 2017 March 31, 2017 Land $ 672 $ 672 Machinery and equipment 1,603 1,698 Office, computer and research equipment 5,473 6,012 Leasehold improvements 1,275 7,680 Land, property and equipment, gross $ 9,023 $ 16,062 Less accumulated depreciation and amortization (7,393 ) (14,078 ) Land, property and equipment, net $ 1,630 $ 1,984

Basis of Presentation (Details

Basis of Presentation (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017		Dec. 31, 2016	Mar. 31, 2017
Business Acquisition [Line Items]
Unbilled Receivables, Current	$ 220,000		$ 220,000			$ 0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax	$ 0	$ 0	$ 608,000	[1]	$ 0
[1]	During the quarter ended September 30, 2017, the Company dissolved the NoranTel legal entity, which triggered a one-time foreign currency gain with the reversal of a cumulative translation adjustment. See Note 1.

Restructuring Charge (Details)

Restructuring Charge (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2017
Restructuring charges
Liability at beginning of period		$ 1,234
Restructuring Charges	$ 490	165	$ 3,055	$ 3,200
Paid		(1,233)
Liability at end of period		166		1,234
Employee Severance [Member]
Restructuring charges
Liability at beginning of period		0
Restructuring Charges		165		1,300
Paid		(165)
Liability at end of period		0		0
Other Restructuring [Member]
Restructuring charges
Liability at beginning of period		1,234
Restructuring Charges		0
Paid		(1,068)
Liability at end of period		$ 166		$ 1,234

Restructuring Charge (Details T

Restructuring Charge (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2017
Restructuring Cost and Reserve [Line Items]
Impairment of Long-Lived Assets to be Disposed of	$ 0	$ 0	$ 0	$ 1,181
Production Related Impairments or Charges				1,600
Impairment of Leasehold					$ 1,200
Restructuring		$ 490	165	$ 3,055	3,200
restructuringexpenseconsultants					700
Unpaid balance of restructuring charges	166		166		1,234
Restructuring Reserve, Noncurrent	0		0		63
Restructuring Reserve, Current	166		166		1,171
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring			165		1,300
Unpaid balance of restructuring charges	0		0		0
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring			0
Unpaid balance of restructuring charges	$ 166		$ 166		$ 1,234

Interim Segment Information (De

Interim Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended				12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2017		Dec. 31, 2016		Mar. 31, 2017
Segment information
Total revenue	$ 13,675		$ 14,983		$ 47,481		$ 47,579
Total cost of revenue (1)	7,599		8,929		27,363		30,593	[1]
Gross profit	$ 6,076		$ 6,054		$ 20,118		$ 16,986	[1]
Gross margin	44.40%		40.40%		42.40%		35.70%	[1]
Research and development	$ 1,542		$ 2,414		$ 6,023		$ 10,018
Segment Profit Loss	4,534		3,640		14,095		6,968
Operating expenses
Sales and marketing	1,950		1,943		6,278		8,220
General and administrative	1,502		1,777		5,022		6,340
Intangible amortization	1,047		1,212		3,142		3,613
Restructuring			490		165		3,055		$ 3,200
Impairment of Long-Lived Assets to be Disposed of	0		0		0		1,181
Operating profit (loss)	35		(1,782)		(512)		(15,441)
Other Nonoperating Income (Expense)	79		(15)		799	[2]	76
Income tax benefit (expense)	685	[3]	(10)		660	[3]	(20)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	799		(1,807)		947		(15,385)
IBW [Member]
Segment information
Total revenue	5,223		6,224		20,098		18,989
Total cost of revenue (1)	2,754		3,713	[1]	10,965		13,251	[1]
Gross profit	$ 2,469		$ 2,511	[1]	$ 9,133		$ 5,738	[1]
Gross margin	47.30%		40.30%	[1]	45.40%		30.20%	[1]
Research and development	$ 750		$ 1,307		$ 3,656		$ 5,265
Segment Profit Loss	1,719		1,204		5,477		473
ISMS [Member]
Segment information
Total revenue	5,802		5,525		14,662		14,773
Total cost of revenue (1)	2,642		2,730		7,157		7,552
Gross profit	$ 3,160		$ 2,795		$ 7,505		$ 7,221
Gross margin	54.50%		50.60%		51.20%		48.90%
Research and development	$ 547		$ 805		$ 1,635		$ 3,336
Segment Profit Loss	2,613		1,990		5,870		3,885
CNS [Member]
Segment information
Total revenue	2,650		3,234		12,721		13,817
Total cost of revenue (1)	2,203		2,486		9,241		9,790
Gross profit	$ 447		$ 748		$ 3,480		$ 4,027
Gross margin	16.90%		23.10%		27.40%		29.10%
Research and development	$ 245		$ 302		$ 732		$ 1,417
Segment Profit Loss	$ 202		$ 446		$ 2,748		$ 2,610
[1]	The nine months ended December 31, 2016, includes $1.6 million of E&O expense for ClearLink DAS inventory and pipeline inventory.
[2]	During the quarter ended September 30, 2017, the Company dissolved the NoranTel legal entity, which triggered a one-time foreign currency gain with the reversal of a cumulative translation adjustment. See Note 1.
[3]	During the quarter ended December 31, 2017, the Company had income tax benefit from the release of the tax valuation allowance associated with previously generated alternative minimum tax (AMT) credits due to the enacted Tax Reform. See Note 8.

Interim Segment Information (36

Interim Segment Information (Details Textual)	9 Months Ended
	Dec. 31, 2017segments
Segment Reporting [Abstract]
Number of Reportable Segments	3

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Mar. 31, 2017
Components of inventories
Raw materials	$ 3,148	$ 3,871
Finished goods	6,316	8,640
Total inventories	$ 9,464	$ 12,511

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Stock-based compensation expense
Stock-based compensation expense	$ 316	$ 253	$ 988	$ 1,346
Income tax benefit	0	0	0	0
Total stock-based compensation expense, after taxes	$ 316	$ 253	$ 988	$ 1,346

Stock-Based Compensation (Det39

Stock-Based Compensation (Details 1) - Employee Stock Option [Member] - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended	12 Months Ended
		Dec. 31, 2017	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding on March 31, 2017		362,396
Granted		100,000
Exercised		0
Forfeited		(199,483)
Expired		(61,018)
Outstanding on December 31, 2017		201,895	362,396
Weighted-Average Exercise Price Per Share, Outstanding on March 31, 2017		$ 4.89
Weighted-Average Exercise Price Per Share, Granted		3.06
Weighted-Average Exercise Price Per Share, Exercised		0
Weighted-Average Exercise Price Per Share, Forfeited		3.72
Weighted-Average Exercise Price Per Share, Expired		5.82
Weighted-Average Exercise Price Per Share, Outstanding on December 31, 2017		$ 4.86	$ 4.89
Weighted-Average Remaining Contractual Term (in years), Outstanding on March 31, 2017		4 years 7 months 13 days	5 years 4 months 24 days
Weighted-Average Remaining Contractual Term (in years), Outstanding on December 31, 2017		4 years 7 months 13 days	5 years 4 months 24 days
Aggregate Intrinsic Value, Outstanding on March 31, 2017	[1]	$ 39
Aggregate Intrinsic Value, Outstanding on December 31, 2017	[1]	$ 76	$ 39
[1]	The intrinsic value for the stock options is calculated based on the difference between the exercise price of the underlying awards and the Westell Technologies’ closing stock price as of the respective reporting date

Stock-Based Compensation (Det40

Stock-Based Compensation (Details 2)	9 Months Ended
	Dec. 31, 2017$ / sharesshares
Restricted Stock [Member]
Restricted stock activity
Non-vested as of March 31, 2017 | shares	34,375
Granted | shares	104,636
Vested | shares	(66,250)
Forfeited | shares	0
Non-vested as of December 31, 2017 | shares	72,761
Weighted-Average Grant Date Fair Value, Non-vested as of March 31, 2017 | $ / shares	$ 4.11
Weighted-Average Grant Date Fair Value, Granted | $ / shares	3.01
Weighted-Average Grant Date Fair Value, Vested | $ / shares	3.30
Weighted-Average Grant Date Fair Value, Forfeited | $ / shares	0
Weighted-Average Grant Date Fair Value, Non-vested as of December 31, 2017 | $ / shares	$ 3.26
Restricted Stock Units (RSUs) [Member]
Restricted stock activity
Non-vested as of March 31, 2017 | shares	373,886
Granted | shares	552,000
Vested | shares	(137,162)
Forfeited | shares	(239,193)
Non-vested as of December 31, 2017 | shares	549,531
Weighted-Average Grant Date Fair Value, Non-vested as of March 31, 2017 | $ / shares	$ 4.48
Weighted-Average Grant Date Fair Value, Granted | $ / shares	2.89
Weighted-Average Grant Date Fair Value, Vested | $ / shares	5.05
Weighted-Average Grant Date Fair Value, Forfeited | $ / shares	3.64
Weighted-Average Grant Date Fair Value, Non-vested as of December 31, 2017 | $ / shares	$ 3.11
Performance Shares [Member]
Restricted stock activity
Non-vested as of March 31, 2017 | shares	76,053
Granted | shares	40,000
Vested | shares	(49,686)
Forfeited | shares	(58,867)
Non-vested as of December 31, 2017 | shares	7,500
Weighted-Average Grant Date Fair Value, Non-vested as of March 31, 2017 | $ / shares	$ 3.56
Weighted-Average Grant Date Fair Value, Granted | $ / shares	3.06
Weighted-Average Grant Date Fair Value, Vested | $ / shares	2.30
Weighted-Average Grant Date Fair Value, Forfeited | $ / shares	2.79
Weighted-Average Grant Date Fair Value, Non-vested as of December 31, 2017 | $ / shares	$ 15.30

Stock-Based Compensation (Det41

Stock-Based Compensation (Details Textual)	9 Months Ended
	Dec. 31, 2017
2004 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting schedule of equal annual installments	4 years
Restricted Stock Units (RSUs) [Member] | 2015 Omnibus Incentive Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting schedule of equal annual installments	3 years
Restricted Stock [Member] | 2015 Omnibus Incentive Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting schedule of equal annual installments	1 year

Product Warranties (Details)

Product Warranties (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Changes in Company's standard product warranty reserve [Roll Forward]
Total product warranty reserve at the beginning of the period	$ 446	$ 460	$ 395	$ 436
Warranty expense to cost of revenue	42	12	160	80
Utilization	(39)	(2)	(106)	(46)
Total product warranty reserve at the end of the period	$ 449	$ 470	$ 449	$ 470

Product Warranties (Details Tex

Product Warranties (Details Textual) - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2017	Mar. 31, 2017
Product Warranties (Textual) [Abstract]
Current portions of warranty reserve	$ 162	$ 163
Non-current portions of the warranty reserve	$ 287	$ 232
IBW [Member] | Minimum [Member]
Product Warranties (Textual) [Abstract]
Standard Product Warranty Description	P1Y
IBW [Member] | Maximum [Member]
Product Warranties (Textual) [Abstract]
Standard Product Warranty Description	P5Y
ISMS [Member]
Product Warranties (Textual) [Abstract]
Standard Product Warranty Description	P1Y
CNS [Member] | Minimum [Member]
Product Warranties (Textual) [Abstract]
Standard Product Warranty Description	P1Y
CNS [Member] | Maximum [Member]
Product Warranties (Textual) [Abstract]
Standard Product Warranty Description	P7Y

Variable Interest Entity and 44

Variable Interest Entity and Guarantee (Details Textual) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2017	Apr. 02, 2013
Concentration Risk [Line Items]
Total revenue	$ 13,675		$ 14,983	$ 47,481	$ 47,579
AKA [Member]
Concentration Risk [Line Items]
Equity Method Investments	61			61		$ 111
Dividend Income, Operating		$ 59
Total revenue	1,500		$ 300	3,200	$ 2,000
Accounts Receivable, Net, Current	1,000			1,000		500
Deferred Revenue	1,500			1,500		$ 2,800
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 700			$ 700
AKA [Member]
Concentration Risk [Line Items]
Equity Method Investment, Ownership Percentage							50.00%

Income Taxes (Details Textual)

Income Taxes (Details Textual) - USD ($)	3 Months Ended				9 Months Ended			12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2017		Dec. 31, 2016	Mar. 31, 2018
Subsequent Event [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent					34.00%
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount					$ 14,300,000
Deferred Tax Assets, Gross		$ 38,600,000			38,600,000
Deferred Tax Assets, Valuation Allowance		38,600,000			38,600,000
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax		697,000			697,000
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability					697,000
Income Taxes (Textual) [Abstract]
Income tax benefit (expense)		$ 685,000	[1]	$ (10,000)	$ 660,000	[1]	$ (20,000)
Effective tax rate					1.76%		(0.13%)
Subsequent Event [Member]
Subsequent Event [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Scenario, Forecast [Member]
Subsequent Event [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent								30.75%
[1]	During the quarter ended December 31, 2017, the Company had income tax benefit from the release of the tax valuation allowance associated with previously generated alternative minimum tax (AMT) credits due to the enacted Tax Reform. See Note 8.

Short-term Investments (Details

Short-term Investments (Details) - USD ($)	Dec. 31, 2017	Mar. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Short-term Investments	$ 4,537,000	$ 0

Fair Value Measurements (Detail

Fair Value Measurements (Details) - Recurring [Member] - Cash and cash equivalents [Member] - USD ($) $ in Thousands	Dec. 31, 2017	Mar. 31, 2017
Assets and liabilities measured at fair value on a recurring basis and their related valuation inputs
Money market funds	$ 12,724	$ 17,162
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets and liabilities measured at fair value on a recurring basis and their related valuation inputs
Money market funds	$ 12,724	$ 17,162

Share Repurchases (Details Text

Share Repurchases (Details Textual) - Class A Common Stock - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	May 17, 2017	Mar. 31, 2017	Aug. 31, 2011
MayTwoThousandSeventeenAuthorization [Member]
Share Repurchases (Textual) [Abstract]
Stock Repurchase Program			$ 2
Treasury Stock, Shares, Acquired	133,608
Stock Repurchase Program Remaining Authorized Repurchases Amount	$ 1.7
Treasury stock acquired volume weighted-average price	$ 2.98
August 2011 authorization [Member]
Share Repurchases (Textual) [Abstract]
Stock Repurchase Program					$ 20
Treasury Stock, Shares, Acquired		0
Stock Repurchase Program Remaining Authorized Repurchases Amount				$ 0.1
Outside of Publically Announced Repurchase Program [Member]
Share Repurchases (Textual) [Abstract]
Treasury Stock, Shares, Acquired	54,572	44,005
Treasury stock acquired volume weighted-average price	$ 2.89	$ 3.32

Intangibles Assets (Details)

Intangibles Assets (Details) - USD ($)	3 Months Ended	9 Months Ended
	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived		$ 0
ISMS [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived			$ 0
IBW [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived			$ 0
CNS [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived	$ 31,000

Accrued Liabilities (Details Te

Accrued Liabilities (Details Textual) - USD ($) $ in Thousands	Dec. 31, 2017	Mar. 31, 2017
Accrued Liabilities [Abstract]
Employee-related Liabilities, Current	$ 731	$ 1,256
Liabilities of Business Transferred under Contractual Arrangement, Current	1,445	1,445
Other Liabilities	1,352	1,572
Accrued Liabilities, Current	$ 3,528	$ 4,273

Land Property and Equipment (De

Land Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Mar. 31, 2017
Property, Plant and Equipment [Line Items]
Land	$ 672	$ 672
Machinery and equipment	1,603	1,698
Office, computer and research equipment	5,473	6,012
Leasehold improvements	1,275	7,680
Land, property and equipment, gross	9,023	16,062
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	7,393	14,078
Land, property and equipment, net	$ 1,630	$ 1,984

Land Property and Equipment Tex

Land Property and Equipment Textual (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Impairment of Long-Lived Assets to be Disposed of	$ 0	$ 0	$ 0	$ 1,181