Neophotonics (NPTN) 10-Q 11 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 30, 2015
Document Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	NPTN
Entity Registrant Name	NEOPHOTONICS CORP
Entity Central Index Key	1227025
Current Fiscal Year End Date	-19
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		32,900,509

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$62,002	$43,035
Short-term investments	8,296
Restricted cash and investments	4,006	5,504
Accounts receivable, net of allowance for doubtful accounts	85,803	77,597
Inventories, net	64,729	57,347
Prepaid expenses and other current assets	14,088	15,540
Total current assets	238,924	199,023
Property, plant and equipment, net	61,853	57,657
Restricted cash and investments, non-current		15,750
Purchased intangible assets, net	13,787	10,263
Goodwill	1,141
Other long-term assets	2,145	3,591
Total assets	317,850	286,284
Current liabilities:
Accounts payable	55,664	48,949
Notes payable and short-term borrowing	22,921	22,771
Current portion of long-term debt	16,138	2,445
Accrued and other current liabilities	23,927	22,728
Total current liabilities	118,650	96,893
Long-term debt, net of current portion	27,115	20,891
Deferred income tax liabilities	1,823	1,818
Other noncurrent liabilities	7,627	7,226
Total liabilities	155,215	126,828
Commitments and contingencies (Note 10)
Stockholders’ equity:
Preferred stock, $0.0025 par value At March 31, 2015 and December 31, 2014: 10,000 shares authorized, no shares issued or outstanding
At March 31, 2015: 100,000 shares authorized, 32,897 shares issued and outstanding; At December 31, 2014: 100,000 shares authorized, 32,752 shares issued and outstanding	82	82
100,000 shares authorized, 32,752 shares issued and outstanding	458,583	456,189
Accumulated other comprehensive income	6,011	5,326
Accumulated deficit	-302,041	-302,141
Total stockholders’ equity	162,635	159,456
Total liabilities and stockholders’ equity	$317,850	$286,284

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Statement Of Financial Position [Abstract]
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	32,897,000	32,752,000
Common stock, shares outstanding	32,897,000	32,752,000

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Income Statement [Abstract]
Revenue	$81,384	$68,168
Cost of goods sold	57,331	54,368
Gross profit	24,053	13,800
Operating expenses:
Research and development	10,482	12,056
Sales and marketing	3,744	3,411
General and administrative	8,196	8,987
Amortization of purchased intangible assets	449	379
Acquisition-related transaction costs	140
Restructuring charges	6
Total operating expenses	23,017	24,833
Income (loss) from operations	1,036	-11,033
Interest income	30	65
Interest expense	-506	-251
Other expense, net	-46	-607
Total interest and other expense, net	-522	-793
Income (loss) before income taxes	514	-11,826
Income tax provision	-414	-762
Net income (loss)	$100	($12,588)
Net income (loss) per share:
Basic		($0.40)
Diluted		($0.40)
Weighted average shares used in computing per share amounts:
Basic	32,780	31,610
Diluted	33,031	31,610

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (Loss) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$100	($12,588)
Foreign currency translation adjustments, net of tax of zero	688	-1,599
Defined benefit pension plans adjustment, net of tax of zero and $73, respectively		118
Unrealized (loss) gain on investments, net of tax of zero	-3	3
Comprehensive income (loss)	$785	($14,066)

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Comprehensive Income ( Loss) (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Foreign currency translation adjustments, tax	$0	$0
Defined benefit pension plans adjustment, tax	0	73
Unrealized (loss) gains on investments, tax	$0	$0

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities
Net income (loss)	$100	($12,588)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	6,306	5,528
Stock-based compensation expense	2,056	1,901
Deferred taxes	3	76
Investment and debt related amortization	28	56
(Gain) loss on disposal of property and equipment	-118	15
Adjustment to fair value of penalty payment derivative		186
Allowance for doubtful accounts	51	-84
Write-down of inventories	1,317	567
Other, net	288	-333
Change in assets and liabilities, net of effects of acquisitions:
Accounts receivable	1,228	-6,643
Inventories	-6,883	-4,413
Prepaid expenses and other assets	2,041	-2,512
Accounts payable	-624	9,168
Accrued and other liabilities	2,032	1,719
Acquisition related transaction costs	-379
Net cash provided by (used in) operating activities	7,446	-7,357
Cash flows from investing activities
Purchase of property, plant and equipment	-2,160	-2,070
Proceeds from sale of property, plant and equipment	103
Purchase of marketable securities		-5,072
Proceeds from sale of marketable securities		9,644
Proceeds from maturity of securities		5,007
Decrease (increase) in restricted cash	8,968	-879
Net cash provided by investing activities	6,911	6,630
Cash flows from financing activities
Proceeds from exercise of stock options	20	303
Tax withholding on restricted stock units	-185	-80
Payments of deferred offering costs	-233
Proceeds from bank loans	12,134
Repayment of bank and acquisition-related loans	-7,695	-5,157
Proceeds from issuance of notes payable	5,575	6,178
Repayment of notes payable	-5,478	-4,448
Net cash provided by (used in) financing activities	4,138	-3,204
Effect of exchange rates on cash and cash equivalents	472	-114
Net increase (decrease) in cash and cash equivalents	18,967	-4,045
Cash and cash equivalents at the beginning of the period	43,035	57,101
Cash and cash equivalents at the end of the period	62,002	53,056
Supplemental disclosure of noncash investing and financing activities:
Issuance of notes to the seller of acquired business	15,482
Modification of bank loan	15,786
Transfer of restricted investments to short-term investments	$8,296

Basis_of_Presentation_and_Sign

Basis of Presentation and Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation and Significant Accounting Policies	Note 1. Basis of presentation and significant accounting policies
	Basis of Presentation and Consolidation
	The condensed consolidated financial statements of NeoPhotonics Corporation (“NeoPhotonics” or the “Company”) as of March 31, 2015 and for the three months ended March 31, 2015 and 2014, have been prepared in accordance with the instructions on Form 10-Q pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). In accordance with those rules and regulations, the Company has omitted certain information and notes normally provided in the Company’s annual consolidated financial statements. In the opinion of management, the condensed consolidated financial statements contain all adjustments, consisting only of normal recurring items, except as otherwise noted, necessary for the fair presentation of the Company’s financial position and results of operations for the interim periods. The year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by U.S. generally accepted accounting principles (“U.S. GAAP”). These condensed consolidated financial statements should be read in conjunction with the Consolidated Financial Statements and Notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2014. The results of operations for the three months ended March 31, 2015 are not necessarily indicative of the results expected for the entire fiscal year. All significant intercompany accounts and transactions have been eliminated.
	Certain Significant Risks and Uncertainties
	The Company operates in a dynamic industry and, accordingly, can be affected by a variety of factors.  For example, any of the following areas could have a negative effect on the Company in terms of its future financial position, results of operations or cash flows: the general state of the U.S., China and world economies, the highly cyclical nature of the industries the Company serves; the loss of any of a small number of its larger customers; ability to obtain additional financing; inability to meet certain debt covenants; failure to successfully integrate completed acquisitions; fundamental changes in the technology underlying the Company’s products; the hiring, training and retention of key employees; successful and timely completion of product design efforts; and new product design introductions by competitors.
	Concentration
	In the three months ended March 31, 2015, Huawei Technologies and their affiliate HiSilicon Technologies (“Huawei”) and Ciena Corporation (“Ciena”) accounted for 40% and 23% of the Company’s total revenue, respectively, and the Company’s top ten customers represented 90% of its total revenue. In the three months ended March 31, 2014, Huawei, Ciena and Alcatel-Lucent SA each accounted for 35%, 14% and 13% of the Company’s total revenue, respectively, and the top ten customers represented 88% of its total revenue.
	As of March 31, 2015, two customers accounted for 44% and 16% of the Company’s total accounts receivable. As of December 31, 2014, two customers accounted for 45% and 10% of the Company’s total accounts receivable.
	Use of Estimates
	The preparation of financial statements in accordance with U.S. 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 the reported revenue and expenses during the reporting period. Significant estimates made by management include: the useful lives of property, plant and equipment and intangible assets as well as future cash flows to be generated by those assets; fair values of identifiable assets acquired and liabilities assumed in business combinations; allowances for doubtful accounts; valuation allowances for deferred tax assets; valuation of excess and obsolete inventories; warranty reserves; and recognition of stock-based compensation, among others. Actual results could differ from these estimates.
	Summary of Significant Accounting Policies
	There have been no changes in the Company’s significant accounting policies for the three months ended March 31, 2015, as compared to the significant accounting policies described in its Annual Report on Form 10-K for the year ended December 31, 2014.
	Recent accounting pronouncements
	In April 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") 2015-03, Simplifying the Presentation of Debt Issuance Costs (“ASU 2015-03”). ASU 2015-03 requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. ASU 2015-03 is effective for the Company’s annual and interim reporting periods beginning after December 15, 2015, with early adoption permitted. The Company is in the process of evaluating the impact of adoption on its consolidated financial statements.
	In January 2015, the FASB issued ASU 2015-01, Income Statement – Extraordinary and Unusual Items (“ASU 2015-01”), which eliminates from U.S. GAAP the concept of extraordinary items. The guidance eliminates the separate presentation of extraordinary items on the income statement, net of tax and the related earnings per share, but does not affect the requirement to disclose material items that are unusual in nature or occurring infrequently. The new standard may be applied prospectively or retrospectively and is effective for annual reporting periods beginning after December 15, 2015 and interim periods within those annual periods, with early adoption permitted. The Company does not expect the adoption of this standard to have an impact on its consolidated financial statements.
	In November 2014, the FASB issued ASU 2014-16, Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share is More Akin to Debt or to Equity (“ASU 2014-16”). ASU 2014-16 requires entities to determine the nature of the host contract by considering all stated and implied substantive terms and features of the hybrid financial instrument, weighing each term and feature on the basis of the relevant facts and circumstances. This ASU is effective for the Company’s annual and interim reporting periods after December 31, 2015, with early adoption permitted. The Company is in the process of evaluating the impact of adoption on its consolidated financial statements.
	In August 2014, the FASB issued ASU No. 2014-15, Disclosure of Uncertainties About an Entity’s Ability to Continue as a Going Concern  (“ASU 2014-15”), which requires management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date the financial statements are issued. An entity must provide certain disclosures in its financial statements if conditions or events raise substantial doubt about its ability to continue as a going concern. ASU 2014-15 is effective for the Company’s annual reporting period ending December 31, 2016, and interim periods thereafter, with early adoption permitted. The Company is in the process of evaluating the impact of adoption on its consolidated financial statements.
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). The standard provides companies with a single model for use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific revenue guidance. The core principle of the model is to recognize revenue when control of the goods or services transfers to the customer, as opposed to recognizing revenue when the risks and rewards transfer to the customer under the existing revenue guidance. ASU 2014-09 is effective for annual and interim reporting periods beginning after December 15, 2016. Early adoption is not permitted. In April 2015, the FASB issued a proposed ASU to defer for one year the effective date of the ASU 2014-09 to annual and interim periods beginning after December 15, 2017 and permits entities to early adopt the standard as of ASU 2014-09’s original effective date. The guidance permits companies to either apply the requirements retrospectively to all prior periods presented, or apply the requirements in the year of adoption, through a cumulative adjustment.  The Company is in the process of evaluating the impact of adoption on its consolidated financial statements.
	In April 2014, the FASB issued ASU No. 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity ("ASU 2014-08") which raises the threshold for a disposal to qualify as a discontinued operation and requires new disclosures of both discontinued operations and certain other disposals that do not meet the definition of a discontinued operation. ASU 2014-08 is effective for annual periods beginning on or after December 15, 2014. The Company’s adoption of this guidance on January 1, 2015 did not impact its consolidated financial statements.

Net_Income_Loss_per_Share

Net Income (Loss) per Share	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Net Income (Loss) per Share	Note 2. Net income (loss) per share
	The following table sets forth the computation of the basic and diluted net income (loss) per share for the periods indicated (in thousands, except per share amounts):
			Three months ended
			March 31,
			2015				2014
	Numerator:
	Net income (loss)		$	100		$	(12,588	)
	Denominator:
	Weighted average shares used in computing per share amount:
	Basic			32,780			31,610
	Dilutive effect of employee stock awards			251			—
	Diluted			33,031			31,610
	Net income (loss) per share – Basic and Diluted		$	—		$	(0.40	)
	The Company has excluded the impact of following outstanding employee stock options, restricted stock units, common stock warrants and shares expected to be issued under its employee stock purchase plan from the computation of diluted net loss per share as their effect would have been antidilutive (in thousands):
		March 31,
		2015			2014
	Employee stock options		4,930			3,952
	Restricted stock units		400			1,134
	Employee stock purchase plan		—			469
	Common stock warrants		—			4
			5,330			5,559

Cash_Cash_Equivalents_and_Shor

Cash, Cash Equivalents and Short-Term Investments and Restricted Cash and Investments	3 Months Ended
	Mar. 31, 2015
Cash And Cash Equivalents [Abstract]
Cash, Cash Equivalents and Short-Term Investments and Restricted Cash and Investments	Note 3. Cash, cash equivalents, short-term investments and restricted cash and investments
	The following table summarizes the Company’s cash, cash equivalents, short-term investments, and restricted cash and investments at March 31, 2015 and December 31, 2014 (in thousands):
		March 31,			December 31,
		2015			2014
	Cash and cash equivalents:
	Cash	$	54,553		$	43,035
	Cash equivalents		7,449			—
	Cash and cash equivalents	$	62,002		$	43,035
	Short-term investments	$	8,296		$	—
	Restricted cash and investments:
	Restricted cash and investments, current	$	4,006		$	5,504
	Restricted cash and investments, non-current		—			15,750
	Total restricted cash and investments	$	4,006		$	21,254
	The following table summarizes the Company’s unrealized gains and losses related to the cash equivalents, short-term investments and restricted investments in marketable securities designated as available-for-sale (in thousands):
			As of March 31, 2015									As of December 31, 2014
			Amortized			Gross		Gross		Fair		Amortized		Gross		Gross		Fair
			Cost			Unrealized		Unrealized		Value		Cost		Unrealized		Unrealized		Value
						Gains		Losses						Gains		Losses
	Cash equivalents
	Money market funds		$	—		$	—	$	—	$	—	$	—	$	—	$	—	$	—
	Time deposits			—			—		—		—		—		—		—		—
	Total		$	—		$	—	$	—	$	—	$	—	$	—	$	—	$	—
	Short-term investments and restricted investments
	Money market funds		$	4,585		$	—	$	—	$	4,585	$	4,587	$	—	$	—	$	4,587
	Corporate bonds			2,008			3		—		2,011		2,004		6		—		2,010
	Variable rate demand notes			1,700			—		—		1,700		1,700		—		—		1,700
	Total short-term investments and restricted investments		$	8,293		$	3	$	—	$	8,296	$	8,291	$	6	$	—	$	8,297
	Reported within:
	Short-term investments		$	8,293		$	3	$	—	$	8,296	$	—	$	—	$	—	$	—
	Restricted cash and investments, non-current			—			—		—		—		8,291		6	$	—	$	8,297
	Total		$	8,293		$	3	$	—	$	8,296	$	8,291	$	6	$	—	$	8,297
	As of March 31, 2015 and December 31, 2014, maturities of marketable securities were as follows (in thousands):
		March 31,			December 31,
		2015			2014
	Less than 1 year	$	6,596		$	6,597
	Due in 1 to 2 years		—			—
	Due in 2 to 5 years		—			—
	Due after 5 years		1,700			1,700
	Total	$	8,296		$	8,297
	The Company may sell its investments in the future to fund future operating needs. As a result, the Company recorded all its marketable securities in short-term investments as of March 31, 2015 and December 31, 2014, regardless of the contractual maturity date of the securities. Variable rate demand notes (“VRDNs”) are floating rate municipal bonds with embedded put options that allow the bondholder to sell the security at par plus accrued interest. All of the put options are secured by a pledged liquidity source. While they are classified as short-term investments, the put option allows the VRDNs to be liquidated at par on a seven-day settlement basis.
	Realized gains and losses on the sale of marketable securities during the three months ended March 31, 2015 and 2014 were immaterial. The Company did not recognize any impairment losses on its marketable securities during the three months ended March 31, 2015 or 2014. As of March 31, 2015, the Company did not have any investments in marketable securities that were in an unrealized loss position for a period in excess of 12 months.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 4.  Fair value measurements
	Assets and Liabilities Measured at Fair Value on a Recurring Basis
	The following table presents the Company's assets that are measured at fair value on a recurring basis (in thousands):
		As of March 31, 2015								As of December 31, 2014
		Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
	Short-term investments and restricted investments:
	Money market funds	$	4,585	$	—	$	—	$	4,585	$	4,587	$	—	$	—	$	4,587
	Corporate bonds		—		2,011		—		2,011		—		2,010		—		2,010
	Variable rate demand notes		—		1,700		—		1,700		—		1,700		—		1,700
	Total	$	4,585	$	3,711	$		$	8,296	$	4,587	$	3,710	$	—	$	8,297
	Mutual funds held in Rabbi Trust, recorded in other long-term assets	$	450	$	—	$	—	$	450	$	424	$	—	$	—	$	424
	The Company offers a Non-Qualified Deferred Compensation Plan (“NQDC Plan”) to a select group of its highly compensated employees.  The NQDC Plan provides participants the opportunity to defer payment of certain compensation as defined in the NQDC Plan.  A Rabbi Trust has been established to fund the NQDC Plan obligation, which was fully funded at March 31, 2015.  The assets held by the Rabbi Trust are substantially in the form of exchange traded mutual funds and are included in the Company’s other long-term assets on its condensed consolidated balance sheets as of March 31, 2015 and December 31, 2014.
	The following table presents the Company's liabilities that are measured at fair value on a recurring basis (in thousands):
		As of March 31, 2015								As of December 31, 2014
		Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
	Penalty payment derivative (Note 10)	$	—	$	—	$	530	$	530	$	—	$	—	$	530	$	530
	There were no transfers between levels of the fair value hierarchy during the periods presented.
	Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
	There were no assets or liabilities measured at fair value on a nonrecurring basis as of March 31, 2015 or December 31, 2014.
	Assets and Liabilities Not Measured at Fair Value
	The carrying values of cash, restricted cash, accounts receivable, accounts payable, notes payable and short-term borrowings approximate their fair values due to the short-term nature and liquidity of these financial instruments.
	The fair values of the Company’s long-term debt have been calculated using an estimate of the interest rate the Company would have had to pay on the issuance of liabilities with a similar maturity and discounting the cash flows at that rate which it considers to be a level 2 fair value measurement. The fair values do not necessarily give an indication of the amount that the Company would currently have to pay to extinguish any of this debt.
	The fair value of the Company’s variable rate bank borrowings was not materially different than its carrying value as of March 31, 2015 and December 31, 2014 as the interest rates approximated rates available to the Company and the fair value of the Company’s acquisition-related debt approximated its carrying value.

Business_Combination

Business Combination	3 Months Ended
	Mar. 31, 2015
Business Combinations [Abstract]
Business Combinations	Note 5. Business combination
	On January 2, 2015, the Company closed an acquisition of the tunable laser product lines of EMCORE Corporation (“EMCORE”) for an original purchase price of $17.5 million. Consideration for the transaction consisted of $1.5 million in cash and a promissory note (the “EMCORE Note”) of approximately $16.0 million, which was subject to certain adjustments for inventory, net accounts receivable and pre-closing revenues, and was subsequently adjusted to $15.5 million in connection with a True-Up Confirmation Agreement (the “True-Up Agreement”) executed by and between the Company and EMCORE on April 16, 2015 (see Note 14). The adjusted purchase price for the acquisition was approximately $17.0 million.
	The Company accounted for this acquisition as a business combination. With this acquisition, the Company aims to strengthen its narrow line width tunable laser product portfolio.
	In connection with the acquisition, the Company incurred approximately $0.8 million in total acquisition-related costs related to legal, accounting and other professional services. The acquisition costs were expensed as incurred and included in operating expenses in the Company’s condensed consolidated statement of operations.
	The Company allocated the purchase price of this acquisition to tangible and identifiable intangible assets acquired and liabilities assumed, based on their estimated fair values as of the close of the acquisition. These estimates were determined through established and generally accepted valuation techniques. The Company recorded $1.1 million in goodwill, which represented the excess of the purchase price over the aggregate net estimated fair values of the assets acquired and liabilities assumed in the acquisition.
	The following table summarizes the allocation of the assets acquired and liabilities assumed as of the acquisition date and subsequent adjustments (in thousands):
	Total purchase consideration:
	Cash paid	$	1,500
	Notes payable		15,482
			16,982
	Fair value of assets acquired:
	Accounts receivable, net of allowance for doubtful accounts of $836	$	9,433
	Inventories, net of inventory reserves of $616		1,582
	Prepaid expenses and other current assets		654
	Property, plant and equipment		6,917
	Intangible assets acquired:
	Developed technology		4,100
	Customer relationships		700
		$	23,386
	Less: fair value of liabilities assumed:
	Accounts payable	$	(7,427	)
	Accrued liabilities		(118	)
		$	(7,545	)
	Goodwill	$	1,141
	Purchased intangibles with finite lives will be amortized on a straight-line basis over their respective estimated useful lives. The following table presents details of the purchase price allocated to the acquired intangible assets at the acquisition date:
		Useful			Purchased
		Life			intangible assets
		(In years)			(In thousands)
	Developed technology	7		$	4,100
	Customer relationships	2			700
	Total purchased intangible assets			$	4,800
	The following unaudited supplemental pro forma information presents the combined results of operations of NeoPhotonics Corporation and the assets and liabilities for the three months ended March 31, 2015 and 2014 as though the companies had been combined as of the beginning of the period presented. The pro forma financial information consists of the adjustments of $0.1 million of transaction costs, and an immaterial amount of employee expense. Incremental intangible amortization, inventory and depreciation adjustments and transaction costs were also added to the 2014 period. There were no sales between EMCORE and the Company in the three months ended March 31, 2015 and 2014.
	The unaudited pro forma results do not assume any operating efficiencies as a result of the consolidation of operations (in thousands, except per share data):
		Three Months				Three Months
		Ended March 31,				Ended March 31,
		2015				2014
	Revenue	$	81,384			$	77,705
	Net income (loss)	$	191			$	-15,064
	Basic and diluted net income (loss) per share	$	0.01			$	-0.48
	The unaudited pro forma financial information is presented for informational purposes only and is not indicative of the results of operations that would have been achieved had the acquisition taken place at the beginning of the period presented, nor does it intend to be a projection of future results.

Balance_Sheet_Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2015
Balance Sheet Components [Abstract]
Balance Sheet Components	Note 6. Balance sheet components
	Restricted cash and investments
	Restricted cash and investments consist of the following (See Note 8) (in thousands):
		March 31, 2015			December 31, 2014
	Restricted in connection with notes payable	$	4,006		$	3,754
	Restricted in connection with Comerica Bank term loan		—			17,500
	Total restricted cash and investments	$	4,006		$	21,254
	Reported as:
	Restricted cash and investments	$	4,006		$	5,504
	Restricted cash and investments, non-current		—			15,750
	Total restricted cash and investments	$	4,006		$	21,254
	Accounts receivable, net
	Accounts receivable, net consists of the following (in thousands):
		March 31, 2015			December 31, 2014
	Accounts receivable	$	81,347		$	69,839
	Trade notes receivable		5,587			7,999
	Allowance for doubtful accounts		(1,131	)		(241	)
		$	85,803		$	77,597
	Inventories
	Inventories consist of the following (in thousands):
		March 31, 2015			December 31, 2014
	Raw materials	$	27,152		$	23,804
	Work in process		15,576			13,600
	Finished goods (1)		22,001			19,943
		$	64,729		$	57,347
	-1	Finished goods inventory at customers’ vendor managed inventory locations was $8.3 million and $6.4 million as of March 31, 2015 and December 31, 2014, respectively.
	Purchased intangible assets
	Purchased intangible assets consist of the following (in thousands):
		31-Mar-15								December 31, 2014
		Gross			Accumulated			Net		Gross		Accumulated			Net
		Assets			Amortization			Assets		Assets		Amortization			Assets
	Technology and patents	$	38,181		$	(29,295	)	$	8,886	$	34,023	$	(28,402	)	$	5,621
	Customer relationships		15,456			(11,644	)		3,812		14,725		(11,176	)		3,549
	Leasehold interest		1,391			(302	)		1,089		1,386		(293	)		1,093
	Noncompete agreements		862			(862	)		—		862		(862	)		—
		$	55,890		$	(42,103	)	$	13,787	$	50,996	$	(40,733	)	$	10,263
	Amortization expense relating to technology and patents and the leasehold interest intangible assets is included within cost of goods sold, and customer relationships and the non-compete agreements within operating expenses. The following table presents details of the amortization expense of the Company’s purchased intangible assets as reported in the condensed consolidated statements of operations (in thousands):
		Three Months Ended
		March 31,
		2015			2014
	Cost of goods sold	$	839		$	714
	Operating expenses		449			379
	Total	$	1,288		$	1,093
	The estimated future amortization expense of purchased intangible assets as of March 31, 2015, is as follows (in thousands):
	2015 (remaining nine months)	$	3,862
	2016		4,465
	2017		1,328
	2018		1,151
	2019		795
	Thereafter		2,186
		$	13,787
	Accrued and other current liabilities
	Accrued and other current liabilities consist of the following (in thousands):
		March 31, 2015			December 31, 2014
	Employee-related	$	16,216		$	13,635
	Accrued warranty		1,647			1,751
	Penalty payment derivative		530			530
	Deferred income tax liabilities		181			181
	Other		5,353			6,631
		$	23,927		$	22,728
	Warranty Accrual
	The table below summarizes the movement in the warranty accrual, which is included in accrued and other current liabilities (in thousands):
		Three Months Ended
		March 31,
	2015			2014
Beginning balance	$	1,751		$	1,737
Warranty accruals		68			289
Settlements and adjustments		-172			(357	)
Ending balance	$	1,647		$	1,669
Other noncurrent liabilities
Other noncurrent liabilities consist of the following (in thousands):
	March 31, 2015			December 31, 2014
Pension and other employee-related	$	5,407		$	5,355
Other		2,220			1,871
	$	7,627		$	7,226

Restructuring

Restructuring	3 Months Ended
	Mar. 31, 2015
Restructuring And Related Activities [Abstract]
Restructuring	Note 7. Restructuring
	In 2014, the Company initiated a restructuring plan (the “2014 Restructuring Plan”) to refocus on its strategy execution, optimize its structure, and improve operational efficiencies. The 2014 Restructuring Plan consisted of workforce reductions primarily in the U.S. and in China. Restructuring charges recorded in the three months ended March 31, 2015 was immaterial and was included within operating expenses. The remaining restructuring liability is expected to be paid through October 2015.
	The following table summarizes activity associated with restructuring obligations during the three months ended March 31, 2015 (in thousands):
		Workforce			Facilities			Contract		Total
		Reduction						Termination
	Restructuring obligations, December 31, 2014	$	54		$	100		$	—	$	154
	Restructuring costs incurred		6			—			—		6
	Cash payments		(60	)		(30	)		—		(90	)
	Non-cash settlements and other		—			—			—		—
	Restructuring obligations, March 31, 2015	$	—		$	70		$	—	$	70

Debt

Debt	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Debt	Note 8. Debt
	The table below summarizes the carrying amount and weighted average interest rate of the Company’s notes payable and long-term debt (in thousands, except percentages):
		31-Mar-15						31-Dec-14
		Carrying			Weighted			Carrying	Weighted
		Amount			Average			Amount	Average
					Interest				Interest
					Rate				Rate
	Notes payable	$	12,921		—		$	12,771	—
	Short-term borrowing		10,000		3.18	%		10,000	3.18	%
	Total notes payable and short-term borrowing	$	22,921				$	22,771
	Long-term debt, current and non-current:
	Bank borrowings-Comerica Bank	$	15,787		2.92	%	$	17,500	3.16	%
	Bank borrowings-Mitsubishi Bank		12,469		1.53	%		—	—
	Acquisition-related		15,482		5	%		5,836	1.5	%
	Total long-term debt, current and non-current		43,738					23,336
	Unaccreted discount within current portion of long-term debt		(180	)				—
	Unaccreted discount within long-term debt, net of current portion		(305	)				—
	Total long-term debt, net of unaccreted discount	$	43,253				$	23,336
	Reported as:
	Current portion of long-term debt	$	16,138				$	2,445
	Long-term debt, net of current portion		27,115					20,891
	Total long-term debt, net of unaccreted discount	$	43,253				$	23,336
	Notes payable
	The Company regularly issues notes payable to its suppliers in China in exchange for accounts payable. These notes are supported by non-interest bearing bank acceptance drafts issued under the Company’s existing line of credit facility and are due three to six months after issuance. As a condition of the notes payable arrangements, the Company is required to keep a compensating balance at the issuing banks that is a percentage of the total notes payable balance until the amounts are settled.
	At March 31, 2015, the Company’s subsidiary in China had a short-term line of credit facility with a banking institution which expires in June 2015.  Under the agreement, RMB 160.0 million ($26.1 million) can be used for bank acceptance drafts (with a 25% to 30% compensating balance requirement) and up to RMB 120.0 million ($19.6 million) can be used for short-term loans, which will bear interest at varying rates.  In September 2014, the Company’s China subsidiary renewed its second short-term line of credit facility with a banking institution, under which RMB 150.0 million ($24.5 million) can be used for bank acceptance drafts (with a 30% compensating balance requirement) or short-term loans. This line of credit facility expires in September 2015. As of March 31, 2015, the non-interest bearing bank acceptance drafts issued in connection with the Company’s notes payable to its suppliers in China, under these line of credit facilities, had an outstanding balance of $12.9 million.
	As of March 31, 2015 and December 31, 2014, compensating balances relating to these bank acceptance drafts issued to suppliers and the Company’s subsidiaries totaled $4.0 million and $3.8 million, respectively. Compensating balances are classified as restricted cash and investments on the Company’s condensed consolidated balance sheets.
	Short-term borrowing
	In October 2014, the Company’s subsidiary in China entered into a short-term advance financing agreement, under one of its line of credit facilities, to borrow $5.0 million against export sales to its parent company. This financing agreement bears interest at 4.02% per annum. Interest and the principal are due in April 2015. As of March 31, 2015, the outstanding principal balance was $5.0 million.
	In November 2014, the Company’s subsidiary in China entered into a second short-term advance financing agreement, under one of its line of credit facilities, to borrow $5.0 million against export sales to its parent company. This financing agreement bears interest at 2.33% per annum and service fees at 1.00% per annum. Interest, service fees and the principal are due in May 2015. As of March 31, 2015, the outstanding principal balance was $5.0 million.
	Acquisition-related
	In connection with the acquisition of NeoPhotonics Semiconductor on March 29, 2013, the Company was obligated to pay 1,050 million Japanese Yen (“JPY”) in three equal installments on the first, second and third anniversaries of the closing date for the purchase of the real estate used by NeoPhotonics Semiconductor, of which 700 million JPY ($5.8 million) was outstanding as of December 31, 2014. The obligation bore interest at 1.5% per year, payable annually, and was secured by the acquired real estate property. This loan was repaid in full in February 2015.
	As part of the purchase consideration to acquire the tunable laser products of EMCORE in January 2015 (See Note 5), the Company issued the EMCORE Note, as amended, of $15.5 million, which had a maturity of two years from the closing of the transaction and an interest rate of 5% per annum for the first year and 13% per annum for the second year. The interest was payable semi-annually in cash. In addition, the EMCORE Note was subject to prepayment under certain circumstances and was secured by certain of the assets to be sold pursuant to the asset purchase agreement with EMCORE. The EMCORE Note was subordinated to the Company’s existing bank debt in the U.S . The EMCORE Note was repaid in full in April 2015 and, therefore, was classified within the current portion of long-term debt.
	Bank borrowings
	The Company has a credit agreement with Comerica Bank as lead bank in the U.S., which has been amended several times. In January 2015, the Company executed an amendment to its credit agreement with Comerica Bank to refinance the then-outstanding Comerica term loan. Under the Credit Amendment, the $20.0 million revolving credit facility was replaced with a $25.0 million senior secured revolving credit line with the maturity date on November 2, 2016.  In March 2015, the senior secured revolving credit line was further amended to increase the borrowing capacity from $25.0 million to $30.0 million. Borrowings under the amended revolving credit facility bear interest at an interest rate option of a base rate as defined in the agreement plus 1.75% or LIBOR plus 2.75%.  The Credit Amendment also modified the EBITDA and liquidity covenants and eliminated the need to maintain compensating balances (restricted cash). The credit agreement also restricts the Company’s ability to incur certain additional debt or to engage in specified transactions, restricts the payment of dividends and is secured by substantially all of the Company’s U.S. assets, other than intellectual property assets. The Company also repaid the remaining Comerica term loan balance and borrowed $15.8 million under the amended revolving credit facility.
	The components of the credit facilities are as follows:
	—	A $30.0 million revolving credit facility under which there was $15.8 million outstanding at March 31, 2015 and no outstanding borrowing as of December 31, 2014, subject to covenant requirements. Amounts borrowed, if any, are due on or before November 2, 2016 and bear interest at an interest rate option of a base rate as defined in the agreement plus 1.75% or LIBOR plus 2.75%. As of March 31, 2015 the rate on the LIBOR option was 2.92%.
	—	Under the term loan facility, $17.5 million was outstanding at December 31, 2014 which was repaid in full in January 2015. Prior to the repayment, borrowings under the term loan bore interest at an interest rate option of a base rate as defined in the agreement plus 2.0% or LIBOR plus 3.0%.
	The Company’s original credit agreement with Comerica Bank required the maintenance of specified financial covenants, including a debt to EBITDA ratio and liquidity ratios. The Company was not in compliance with the debt to EBITDA covenant at March 31, 2014, which noncompliance was effectively waived in the amendment described below. During 2014, the Company executed an amendment to the credit agreement that waived the testing of certain covenants for compliance, provided that the Company maintained compensating balances equal to outstanding amounts under the credit agreement in accounts for which the bank had sole access.  The Company’s amended credit agreement with Comerica executed in January 2015 eliminated the compensating balance requirement and modified the financial covenants, including the maintenance of a modified EBITDA and certain liquidity covenants. As of March 31, 2015 and December 31, 2014, the amount of the Company’s cash and investments in its compensating balance accounts for the term loan facility with Comerica Bank was zero and $17.5 million, respectively, which was classified as current and non-current restricted cash and investments on the Company’s condensed consolidated balance sheet (see Note 6).
	On February 25, 2015, the Company entered into certain loan agreements and related special agreements (collectively, the “Loan Arrangements”) with the Bank of Tokyo-Mitsubishi UFJ, Ltd. (the “Mitsubishi Bank”) that provided for (i) a term loan in the aggregate principal amount of 500 million JPY ($4.2 million) (the “Term Loan A”) and (ii) a term loan in the aggregate principal amount of one billion JPY ($8.4 million) (the “Term Loan B” and together with the Term Loan A, the “Mitsubishi Bank Loans”). The Mitsubishi Bank Loans are secured by a mortgage on certain real property and buildings owned by our Japanese subsidiary. The full amount of each of the Mitsubishi Bank Loans was drawn on the closing date of February 25, 2015. Interest on the Mitsubishi Bank Loans accrues and is paid monthly based upon the annual rate of the monthly Tokyo Interbank Offer Rate (TIBOR) plus 1.40%. The Term Loan A requires interest only payments until the maturity date of February 23, 2018, with a lump sum payment of the aggregate principal amount on the maturity date. The Term Loan B requires equal monthly payments of principal equal to 8,333,000 JPY until the maturity date of February 25, 2025, with a lump sum payment of the balance of 8,373,000 JPY on the maturity date. Interest on the Term Loan B is accrued based upon monthly TIBOR plus 1.40% and is secured by real estate collateral. In conjunction with the execution of the Bank Loans, the Company paid a loan structuring fee, including consumption tax, of 40,500,000 JPY ($0.3 million).
	The Mitsubishi Bank Loans contain customary representations and warranties and customary affirmative and negative covenants applicable to the Company’s Japanese subsidiary, including, among other things, restrictions on cessation in business, management, mergers or acquisitions. The Mitsubishi Bank Loans contain financial covenants relating to minimum net assets, maximum ordinary loss and a dividends covenant. The Mitsubishi Bank Loans also include customary events of default, including but not limited to the nonpayment of principal or interest, violations of covenants, restraint on business, dissolution, bankruptcy, attachment and misrepresentations. In March 2015, the Company used a portion of the proceeds of the Mitsubishi Bank Loans to repay the then-outstanding loan related to the acquisition of NeoPhotonics Semiconductor, which had an outstanding principal and interest amount of approximately 710 million JPY ($6.0 million) and the remainder will be used for general working capital.
	At March 31, 2015, maturities of long-term debt were as follows (in thousands):
	2015 (remaining nine months)	$	16,109
	2016		16,623
	2017		836
	2018		5,015
	2019		836
	Thereafter		4,319
		$	43,738

Japan_Pension_Plans

Japan Pension Plans	3 Months Ended
	Mar. 31, 2015
Compensation And Retirement Disclosure [Abstract]
Japan Pension Plans	Note 9. Japan pension plans
	In connection with its acquisition of NeoPhotonics Semiconductor on March 29, 2013, the Company assumed responsibility for two defined benefit plans that provide retirement benefits to its NeoPhotonics Semiconductor employees in Japan: the Retirement Allowance Plan (“RAP”) and the Defined Benefit Corporate Pension Plan (“DBCPP”). The RAP is an unfunded plan administered by the Company.  Effective February 28, 2014, the DBCPP was converted to a defined contribution plan (“DCP”).  In May 2014, the semiconductor Optical Components Business Unit of LAPIS Semiconductor Co., Ltd. (“LAPIS”), a wholly-owned subsidiary of Rohm Co., Ltd. of Japan, transferred approximately $2.0 million into the newly formed DCP which was the allowable amount that can be transferred according to the Japanese regulations. LAPIS also paid the Company approximately $0.3 million in connection with the conversion of the plan. Additionally, the Company transferred the net unfunded projected benefit obligation amount from the DBCPP to the RAP and froze the RAP benefit at the February 28, 2014 amount.
	As a result of these changes to the DBCPP and the RAP, the Company recorded a curtailment gain of $0.1 million in the quarter ended March 31, 2014. The pension liability at March 31, 2015 and December 31, 2014 was $5.1 million and is recorded in accrued and other current liabilities and in other noncurrent liabilities on the Company’s condensed consolidated balance sheet.
	The Company contributed $15,000 to the DBCPP from January 1, 2014 to February 28, 2014.  Because the DBCPP transitioned to the DCP on that date, no further contributions to the DBCPP are required.
	Net periodic pension costs associated with these plans included the following components (in thousands):
		Three Months Ended
		31-Mar-15		31-Mar-14
	Service cost	$	—	$	53
	Interest cost		—		13
	Amortization		—		1
	Net periodic pension costs	$	—	$	67

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 10. Commitments and contingencies
	Litigation
	From time to time, the Company is subject to various claims and legal proceedings, either asserted or unasserted, that arise in the ordinary course of business. The Company accrues for legal contingencies if the Company can estimate the potential liability and if the Company believes it is more likely than not that the case will be ruled against it. If a legal claim for which the Company did not accrue is resolved against it, the Company would record the expense in the period in which the ruling was made. The Company does not believe that the ultimate amount of liability, if any, for any pending claims of any type (alone or combined) will materially affect the Company’s financial position, results of operations or cash flows. The ultimate outcome of any litigation is uncertain, however, and unfavorable outcomes could have a material negative impact on the Company’s financial condition and operating results. Regardless of outcome, litigation can have an adverse impact on the Company because of defense costs, negative publicity, diversion of management resources and other factors.
	On January 5, 2010, Finisar Corporation, or Finisar, filed a complaint in the U.S. District Court for the Northern District of California against Source Photonics, Inc., MRV Communications, Inc., Oplink Communications, Inc. and the Company, or collectively, the co-defendants. In the complaint, Finisar alleged infringement of certain of its U.S. patents arising from the codefendants’ respective manufacture, importation, use, sale of or offer to sell certain optical transceiver products. On March 23, 2010, the Company filed an answer to the complaint and counterclaims, asserting two claims of patent infringement and additional claims asserting that Finisar has violated state and federal competition laws and violated its obligations to license on reasonable and non-discriminatory terms. On May 5, 2010, the court dismissed without prejudice all co-defendants (including the Company) except Source Photonics, Inc., on grounds that such claims should have been asserted in four separate lawsuits, one against each defendant. This dismissal without prejudice does not prevent Finisar from bringing a new similar lawsuit against the Company. On January 18, 2011, the Company and Finisar agreed to suspend their respective claims and not to refile the originally asserted claims against each other until at least 90 days after one or more specified events occur resulting in the partial or complete resolution of litigation involving the same Finisar patents between Oplink Communications, Inc. and Finisar. This tolling period expired on April 30, 2012. On May 3, 2012 the Company and Finisar agreed to further toll their respective claims until the refiling of certain of the previously asserted claims from this dispute. As a result, Finisar is permitted to bring a new lawsuit against the Company if it chooses to do so, and the Company may bring new claims against Finisar upon seven days written notice prior to filing such claims. The Company is currently unable to predict the outcome of this dispute and therefore cannot determine the likelihood of loss nor estimate a range of possible loss.
	On January 2, 2013, the Company was served with a lawsuit, filed in Belgium by Laser 2000 Beneluo SA (“Laser 2000”), based on the fact that the Company requested that Santur Corporation terminate the distributor relationship between Santur and Laser 2000 prior to closing of the acquisition of Santur by the Company. The distributor agreement was formally terminated as of January 3, 2012. Laser 2000 claims that the Company owes Laser 2000 commissions from 2011 and the first semester of 2012 in addition to commissions based on European Directive 86/653 on sales representatives. Laser 2000 claims that it is owed outstanding commissions from 2011, commissions for the first semester of 2012, expected commissions and for the Directive 86/653 commissions. The Company paid $492,000 to Laser 2000 as partial settlement of claims and to avoid penalties from the Court and submitted a legal brief to court on September 16, 2013. Laser 2000 filed a response on December 16, 2013 and the Company filed the final rebuttal brief on January 30, 2014. On March 23, 2015, the Belgian Court issued a ruling awarding Laser 2000 approximately one million euros in damages (approximately $1,100,000 at current exchange rates). The Company is appealing this verdict, but is unable to predict the duration or outcome of the appeal or the overall lawsuit at this time. Although the Company does not believe it will ultimately be liable for the full amount of damage, it increased its accrual for net litigation expense relating to this matter in the three months ended March 31, 2015.
	Indemnifications
	In the normal course of business, the Company enters into agreements that contain a variety of representations and warranties and provide for general indemnification. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future, but have not yet been made. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. However, the Company may record charges in the future as a result of these indemnification obligations. As of March 31, 2015, the Company does not have any material indemnification claims that were probable or reasonably possible.
	Leases
	The Company leases various facilities under non-cancelable operating leases expiring through 2023.  Future minimum payments under these operating leases totaled $7.5 million as of March 31, 2015. Rent expense was $0.5 million for each of the three months ended March 31, 2015 and 2014, respectively.
	Penalty Payment Derivative
	In connection with a private placement transaction in 2012, the Company agreed to certain performance obligations including establishing a wholly-owned subsidiary in the Russia and making a $30.0 million investment commitment (the ‘Investment Commitment’) towards the Company’s Russian operations. The Investment Commitment can be partially satisfied by investment outside of the Russian Federation and/or by way of non-cash asset transfers, including but not limited to capital equipment, small tools, intellectual property, and other intangibles.  A minimum of $15.0 million of the Investment Commitment is required to be satisfied by making capital expenditures and the remaining $15.0 million can be satisfied through general working capital and research and development expenditures.  All of the amount for general working capital can be spent either inside or outside of Russia.  At least 80% of the amount expended for research and development expenditure must be spent inside Russia.  General working capital can include acquisition of other businesses or portions thereof to be owned by the Russian subsidiary.
	The purchaser of the common stock has non-transferable veto rights over the Company’s Russian subsidiary’s annual budget during the investment period and must approve non-cash asset transfers to be made in satisfaction of the Investment Commitment.  Spending and/or commitments to spend for general working capital and research and development do not require approval by the purchaser. There are no legal restrictions on the specific usage of the $39.8 million received in the private placement transaction or on withdrawal from the Company’s bank accounts for use in general corporate purposes.
	In March 2015, the Company extended the Investment Commitment deadline to June 30, 2015.  The parties are pursuing an operating plan that recognizes that more than one-third of the investment has been completed, inclusive of non-cash assets, and that levels the remaining investment over a five year period. If the Company fails to meet the Investment Commitment as agreed by the parties, the Company may be required to pay a penalty of up to $5.0 million (the ‘Penalty Payment’) as the sole and exclusive remedy for damages and monetary relief available to the purchaser for failure to meet the Investment Commitment.
	The Company has accounted for the $5.0 million Penalty Payment as an embedded derivative instrument, with the underlying being the performance or nonperformance of meeting the Investment Commitment and initially classified $4.9 million of the $5.0 million as additional paid-in capital and the remaining $0.1 million, representing the estimated fair value of the Penalty Payment derivative, in other noncurrent liabilities.
	The fair value of the Penalty Payment derivative has been estimated at the date of the original common stock sale (April 27, 2012) and at each subsequent balance sheet date using a probability-weighted discounted future cash flow approach using unobservable inputs, which are classified as Level 3 within the fair value hierarchy. The primary inputs for this approach include the probability of achieving the Investment Commitment and a discount rate that approximates the Company’s incremental borrowing rate. After the initial measurement, changes in the fair value of this derivative were recorded in other expense, net. The estimated fair value of this derivative was $0.5 million and $0.5 million at March 31, 2015 and December 31, 2014, respectively.
	Separately, on December 18, 2014, the Company entered into a Commitment to File a Registration Statement and Related Waiver of Registration Rights, whereby Open Joint Stock Company “RUSNANO” or Rusnano waived certain registration rights in connection with a potential offering by the Company of shares of the Company’s common stock, and the Company committed to file with the U.S. Securities and Exchange Commission a resale registration statement on Form S-1 covering the resale of all shares of the Company’s common stock held by Rusnano. The Company filed such resale registration statement on April 6, 2015.  Rusnano also waived its demand registration rights under the original rights agreement and agreed to enter into a lock up agreement with the Company whereby it would agree not to sell any shares of the Company’s common stock, or engage in certain other transactions relating to the Company’s securities, for a period of 60 days from the filing date of the resale registration statement. Rusnano signed such lock up agreement with the Company on April 2, 2015.

Stockholders_Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2015
Stockholders Equity [Abstract]
Stockholders' Equity	Note 11. Stockholders’ equity
	Common Stock
	As of March 31, 2015, the Company had reserved 7,424,305 common stock shares for issuance under its stock option plans, 978,382 common stock shares for issuance under its stock purchase plan.
	Accumulated Other Comprehensive Income, Net of Tax
	The components of accumulated other comprehensive income, net of related taxes, during the three months ended March 31, 2015 were as follows (in thousands):
		March 31, 2015			March 31, 2014
	Foreign currency translation adjustment	$	6,079		$	10,202
	Unrealized gains on available-for-sale securities		3			6
	Defined benefit pension plan adjustment		(71	)		1
		$	6,011		$	10,209
	No amounts were reclassified out of accumulated other comprehensive income during the three months ended March 31, 2015 and 2014 for realized gains or losses on available-for-sale securities.
	Accumulated Deficit
	Approximately $7.1 million of the Company’s accumulated deficit at December 31, 2014 was subject to restriction due to the fact that the Company’s subsidiaries in China are required to set aside at least 10% of their respective accumulated profits each year to fund statutory common reserves as well as allocate a discretional portion of their after-tax profits to their staff welfare and bonus fund.

StockBased_Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	Note 12. Stock-based compensation
	The following table summarizes the stock-based compensation expense recognized for the three months ended March 31, 2015 and 2014 (in thousands):
		Three Months Ended March 31,
		2015				2014
	Cost of goods sold	$	370			$	330
	Research and development		493				707
	Sales and marketing		453				373
	General and administrative		740				491
		$	2,056			$	1,901
	Determining Fair Value
	The Company estimated the fair value of certain stock-based awards using a Black-Scholes-Merton valuation model with the following assumptions:
			Three Months Ended March 31,
			2015		2014
	Stock options
	Weighted-average expected term (years)		5.25		5.12
	Weighted-average volatility		63%		72%
	Risk-free interest rate		1.65%		1.75%
	Expected dividends		—  %		—  %
	Stock appreciation units
	Weighted-average expected term (years)		1.91		2.15
	Weighted-average volatility		57%		59%
	Risk-free interest rate		0.25%-1.10%		0.13% – 0.78%
	Expected dividends		—  %		—  %
	ESPP
	Weighted-average expected term (years)		0.7		0.76
	Weighted-average volatility		58%		54%
	Risk-free interest rate		0.03%-0.13%		0.10 – 0.13%
	Expected dividends		—  %		—  %
	Stock Options and Restricted Stock Units (RSUs)
	The following table summarizes the Company’s stock option and RSU activity in the three months ended March 31, 2015:
		Stock Options						Restricted Stock Units
		Number of					Weighted	Number of				Weighted
		shares					average	units				average
							exercise price					grant date
												fair value
	Balance at December 31, 2014		4,899,713			$	4.07		655,729		$	6.19
	Granted		116,500				3.38		144,954			6.51
	Exercised/Converted		(4,816	)			4.19		(174,372	)		6.57
	Forfeited and canceled		(65,587	)			5.32		(12,268	)		6.18
	Balance at March 31, 2015		4,945,810			$	4.03		614,043		$	6.16
	During the three months ended March 31, 2015, the Company issued fully vested RSUs covering 139,954 shares of common stock to certain eligible employees, in lieu of cash bonus payments earned in 2014, with a total grant date fair value of $0.9 million.
	Stock appreciation units (“SAUs”)
	SAUs are liability classified share-based awards. The Company did not grant any SAUs during the three months ended March 31, 2015 or 2014. As of March 31, 2015 and December 31, 2014, there were 368,995 and 375,833 SAUs outstanding. Outstanding SAUs were re-measured each reporting period at fair value.
	Employee Stock Purchase Plan (“ESPP”)
	As of March 31, 2015 there was $0.3 million of unrecognized stock-based compensation expense for stock purchase rights that will be recognized over the remaining offering period, through November 2015.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Note 13. Income taxes
	The provision for income taxes is based upon the income (loss) before income taxes as follows:
		Three Months Ended March 31,
	(in thousands)	2015		2014
	Income tax provision	$	414	$	762
	The Company’s income tax expense for the three months ended March 31, 2015 and 2014 was primarily related to income taxes of the Company’s non-U.S. operations.
	The Company conducts its business globally and its operating income is subject to varying rates of tax in the United States, China and Japan. Consequently, the Company’s effective tax rate is dependent upon the geographic distribution of its earnings or losses and the tax laws and regulations in each geographical region. Historically, the Company has experienced net losses in the United States and in the short term, expects this trend to continue. One of the Company’s subsidiaries in China has historically qualified for a preferential 15% tax rate available for high technology enterprises as opposed to the statutory 25% tax rate. In November 2014, the Company received the final approval for the preferential tax rate for 2014 to 2016.
	Due to historic losses in the US, the Company has a full valuation allowance on its US federal and state deferred tax assets. Management continues to evaluate the realizability of deferred tax assets and the related valuation allowance. If management's assessment of the deferred tax assets or the corresponding valuation allowance were to change, the Company would record the related adjustment to income during the period in which management makes the determination.
	As of March 31, 2015, there were no material changes to either the nature or the amounts of the uncertain tax positions previously determined for the year ended December 31, 2014.

Subsequent_Events

Subsequent Events	3 Months Ended
	Mar. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	Note 14. Subsequent Events
	Subsequent events, through the filing of this report, included the following:
	True-Up Agreement
	On April 16, 2015, the Company and EMCORE entered into a True-Up Agreement making several adjustments to the terms of the Asset Purchase Agreement between the parties dated October 22, 2014 pursuant to which the Company purchased certain assets and assumed certain liabilities of EMCORE’s tunable laser product lines. Such transaction was completed in January 2015. The True-Up Agreement makes several final adjustments to the Asset Purchase agreement, including, among other things, (i) adjusting the principal amount of the EMCORE Note (the “Amended EMCORE Note”) from $16.0 million to approximately $15.5 million, (ii) agreeing upon final amounts for inventory value adjustment, net accounts receivable adjustment, and revenue purchase price adjustment, and (iii) resolving the treatment of certain accounts receivable for products sold by EMCORE prior to the closing of the transaction.
	Repayment of EMCORE Note
	On April 17, 2015, the Company repaid all outstanding amounts under the Amended EMCORE Note, utilizing cash receipts from collection of its accounts receivable.
	CITIC Bank Loans
	On April 21, 2015, the Company’s China subsidiary executed a $5.0 million advance financing agreement with one of its line of credit facilities at an interest rate based on a six-month LIBOR plus 330 basis points, or approximately 3.71%. Both interest and principal are due on October 8, 2015. On April 23, 2015, the Company’s China subsidiary repaid in full its then-outstanding $5.0 million short-term financing loan maturing in April 2015 (See Note 8).

Basis_of_Presentation_and_Sign1

Basis of Presentation and Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2015
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation
	The condensed consolidated financial statements of NeoPhotonics Corporation (“NeoPhotonics” or the “Company”) as of March 31, 2015 and for the three months ended March 31, 2015 and 2014, have been prepared in accordance with the instructions on Form 10-Q pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). In accordance with those rules and regulations, the Company has omitted certain information and notes normally provided in the Company’s annual consolidated financial statements. In the opinion of management, the condensed consolidated financial statements contain all adjustments, consisting only of normal recurring items, except as otherwise noted, necessary for the fair presentation of the Company’s financial position and results of operations for the interim periods. The year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by U.S. generally accepted accounting principles (“U.S. GAAP”). These condensed consolidated financial statements should be read in conjunction with the Consolidated Financial Statements and Notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2014. The results of operations for the three months ended March 31, 2015 are not necessarily indicative of the results expected for the entire fiscal year. All significant intercompany accounts and transactions have been eliminated.
	Certain Significant Risks and Uncertainties
	The Company operates in a dynamic industry and, accordingly, can be affected by a variety of factors.  For example, any of the following areas could have a negative effect on the Company in terms of its future financial position, results of operations or cash flows: the general state of the U.S., China and world economies, the highly cyclical nature of the industries the Company serves; the loss of any of a small number of its larger customers; ability to obtain additional financing; inability to meet certain debt covenants; failure to successfully integrate completed acquisitions; fundamental changes in the technology underlying the Company’s products; the hiring, training and retention of key employees; successful and timely completion of product design efforts; and new product design introductions by competitors.
Concentration	Concentration
	In the three months ended March 31, 2015, Huawei Technologies and their affiliate HiSilicon Technologies (“Huawei”) and Ciena Corporation (“Ciena”) accounted for 40% and 23% of the Company’s total revenue, respectively, and the Company’s top ten customers represented 90% of its total revenue. In the three months ended March 31, 2014, Huawei, Ciena and Alcatel-Lucent SA each accounted for 35%, 14% and 13% of the Company’s total revenue, respectively, and the top ten customers represented 88% of its total revenue.
	As of March 31, 2015, two customers accounted for 44% and 16% of the Company’s total accounts receivable. As of December 31, 2014, two customers accounted for 45% and 10% of the Company’s total accounts receivable.
Use of Estimates	Use of Estimates
	The preparation of financial statements in accordance with U.S. 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 the reported revenue and expenses during the reporting period. Significant estimates made by management include: the useful lives of property, plant and equipment and intangible assets as well as future cash flows to be generated by those assets; fair values of identifiable assets acquired and liabilities assumed in business combinations; allowances for doubtful accounts; valuation allowances for deferred tax assets; valuation of excess and obsolete inventories; warranty reserves; and recognition of stock-based compensation, among others. Actual results could differ from these estimates.
Recent Accounting Pronouncements	Recent accounting pronouncements
	In April 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") 2015-03, Simplifying the Presentation of Debt Issuance Costs (“ASU 2015-03”). ASU 2015-03 requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. ASU 2015-03 is effective for the Company’s annual and interim reporting periods beginning after December 15, 2015, with early adoption permitted. The Company is in the process of evaluating the impact of adoption on its consolidated financial statements.
	In January 2015, the FASB issued ASU 2015-01, Income Statement – Extraordinary and Unusual Items (“ASU 2015-01”), which eliminates from U.S. GAAP the concept of extraordinary items. The guidance eliminates the separate presentation of extraordinary items on the income statement, net of tax and the related earnings per share, but does not affect the requirement to disclose material items that are unusual in nature or occurring infrequently. The new standard may be applied prospectively or retrospectively and is effective for annual reporting periods beginning after December 15, 2015 and interim periods within those annual periods, with early adoption permitted. The Company does not expect the adoption of this standard to have an impact on its consolidated financial statements.
	In November 2014, the FASB issued ASU 2014-16, Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share is More Akin to Debt or to Equity (“ASU 2014-16”). ASU 2014-16 requires entities to determine the nature of the host contract by considering all stated and implied substantive terms and features of the hybrid financial instrument, weighing each term and feature on the basis of the relevant facts and circumstances. This ASU is effective for the Company’s annual and interim reporting periods after December 31, 2015, with early adoption permitted. The Company is in the process of evaluating the impact of adoption on its consolidated financial statements.
	In August 2014, the FASB issued ASU No. 2014-15, Disclosure of Uncertainties About an Entity’s Ability to Continue as a Going Concern  (“ASU 2014-15”), which requires management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date the financial statements are issued. An entity must provide certain disclosures in its financial statements if conditions or events raise substantial doubt about its ability to continue as a going concern. ASU 2014-15 is effective for the Company’s annual reporting period ending December 31, 2016, and interim periods thereafter, with early adoption permitted. The Company is in the process of evaluating the impact of adoption on its consolidated financial statements.
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). The standard provides companies with a single model for use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific revenue guidance. The core principle of the model is to recognize revenue when control of the goods or services transfers to the customer, as opposed to recognizing revenue when the risks and rewards transfer to the customer under the existing revenue guidance. ASU 2014-09 is effective for annual and interim reporting periods beginning after December 15, 2016. Early adoption is not permitted. In April 2015, the FASB issued a proposed ASU to defer for one year the effective date of the ASU 2014-09 to annual and interim periods beginning after December 15, 2017 and permits entities to early adopt the standard as of ASU 2014-09’s original effective date. The guidance permits companies to either apply the requirements retrospectively to all prior periods presented, or apply the requirements in the year of adoption, through a cumulative adjustment.  The Company is in the process of evaluating the impact of adoption on its consolidated financial statements.
	In April 2014, the FASB issued ASU No. 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity ("ASU 2014-08") which raises the threshold for a disposal to qualify as a discontinued operation and requires new disclosures of both discontinued operations and certain other disposals that do not meet the definition of a discontinued operation. ASU 2014-08 is effective for annual periods beginning on or after December 15, 2014. The Company’s adoption of this guidance on January 1, 2015 did not impact its consolidated financial statements.

Net_Income_Loss_per_Share_Tabl

Net Income (Loss) per Share (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Income (Loss) per Share	The following table sets forth the computation of the basic and diluted net income (loss) per share for the periods indicated (in thousands, except per share amounts):
			Three months ended
			March 31,
			2015				2014
	Numerator:
	Net income (loss)		$	100		$	(12,588	)
	Denominator:
	Weighted average shares used in computing per share amount:
	Basic			32,780			31,610
	Dilutive effect of employee stock awards			251			—
	Diluted			33,031			31,610
	Net income (loss) per share – Basic and Diluted		$	—		$	(0.40	)
Potentially Dilutive Securities Excluded from Computation of Diluted Net Loss per Share Attributable to Common Stockholders	The Company has excluded the impact of following outstanding employee stock options, restricted stock units, common stock warrants and shares expected to be issued under its employee stock purchase plan from the computation of diluted net loss per share as their effect would have been antidilutive (in thousands):
		March 31,
		2015			2014
	Employee stock options		4,930			3,952
	Restricted stock units		400			1,134
	Employee stock purchase plan		—			469
	Common stock warrants		—			4
			5,330			5,559

Cash_Cash_Equivalents_and_Shor1

Cash, Cash Equivalents and Short-Term Investments and Restricted Cash and Investments (Tables)	3 Months Ended
	Mar. 31, 2015
Cash And Cash Equivalents [Abstract]
Summary of Cash, Cash Equivalents and Short-Term investments and Restricted Cash and Investments	The following table summarizes the Company’s cash, cash equivalents, short-term investments, and restricted cash and investments at March 31, 2015 and December 31, 2014 (in thousands):
		March 31,			December 31,
		2015			2014
	Cash and cash equivalents:
	Cash	$	54,553		$	43,035
	Cash equivalents		7,449			—
	Cash and cash equivalents	$	62,002		$	43,035
	Short-term investments	$	8,296		$	—
	Restricted cash and investments:
	Restricted cash and investments, current	$	4,006		$	5,504
	Restricted cash and investments, non-current		—			15,750
	Total restricted cash and investments	$	4,006		$	21,254
Summary of Unrealized Gains and Losses Related to Cash Equivalents and Investments in Marketable Securities	The following table summarizes the Company’s unrealized gains and losses related to the cash equivalents, short-term investments and restricted investments in marketable securities designated as available-for-sale (in thousands):
			As of March 31, 2015									As of December 31, 2014
			Amortized			Gross		Gross		Fair		Amortized		Gross		Gross		Fair
			Cost			Unrealized		Unrealized		Value		Cost		Unrealized		Unrealized		Value
						Gains		Losses						Gains		Losses
	Cash equivalents
	Money market funds		$	—		$	—	$	—	$	—	$	—	$	—	$	—	$	—
	Time deposits			—			—		—		—		—		—		—		—
	Total		$	—		$	—	$	—	$	—	$	—	$	—	$	—	$	—
	Short-term investments and restricted investments
	Money market funds		$	4,585		$	—	$	—	$	4,585	$	4,587	$	—	$	—	$	4,587
	Corporate bonds			2,008			3		—		2,011		2,004		6		—		2,010
	Variable rate demand notes			1,700			—		—		1,700		1,700		—		—		1,700
	Total short-term investments and restricted investments		$	8,293		$	3	$	—	$	8,296	$	8,291	$	6	$	—	$	8,297
	Reported within:
	Short-term investments		$	8,293		$	3	$	—	$	8,296	$	—	$	—	$	—	$	—
	Restricted cash and investments, non-current			—			—		—		—		8,291		6	$	—	$	8,297
	Total		$	8,293		$	3	$	—	$	8,296	$	8,291	$	6	$	—	$	8,297
Maturities of Marketable Securities	As of March 31, 2015 and December 31, 2014, maturities of marketable securities were as follows (in thousands):
		March 31,			December 31,
		2015			2014
	Less than 1 year	$	6,596		$	6,597
	Due in 1 to 2 years		—			—
	Due in 2 to 5 years		—			—
	Due after 5 years		1,700			1,700
	Total	$	8,296		$	8,297

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets	The following table presents the Company's assets that are measured at fair value on a recurring basis (in thousands):
		As of March 31, 2015								As of December 31, 2014
		Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
	Short-term investments and restricted investments:
	Money market funds	$	4,585	$	—	$	—	$	4,585	$	4,587	$	—	$	—	$	4,587
	Corporate bonds		—		2,011		—		2,011		—		2,010		—		2,010
	Variable rate demand notes		—		1,700		—		1,700		—		1,700		—		1,700
	Total	$	4,585	$	3,711	$		$	8,296	$	4,587	$	3,710	$	—	$	8,297
	Mutual funds held in Rabbi Trust, recorded in other long-term assets	$	450	$	—	$	—	$	450	$	424	$	—	$	—	$	424
Fair Value of Financial Liabilities	The following table presents the Company's liabilities that are measured at fair value on a recurring basis (in thousands):
		As of March 31, 2015								As of December 31, 2014
		Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
	Penalty payment derivative (Note 10)	$	—	$	—	$	530	$	530	$	—	$	—	$	530	$	530

Business_Combination_Tables

Business Combination (Tables)	3 Months Ended
	Mar. 31, 2015
Business Combinations [Abstract]
Summary of Purchase Accounting and Tangible and Intangible Assets Acquired	The following table summarizes the allocation of the assets acquired and liabilities assumed as of the acquisition date and subsequent adjustments (in thousands):
	Total purchase consideration:
	Cash paid	$	1,500
	Notes payable		15,482
			16,982
	Fair value of assets acquired:
	Accounts receivable, net of allowance for doubtful accounts of $836	$	9,433
	Inventories, net of inventory reserves of $616		1,582
	Prepaid expenses and other current assets		654
	Property, plant and equipment		6,917
	Intangible assets acquired:
	Developed technology		4,100
	Customer relationships		700
		$	23,386
	Less: fair value of liabilities assumed:
	Accounts payable	$	(7,427	)
	Accrued liabilities		(118	)
		$	(7,545	)
	Goodwill	$	1,141
Purchase Price Allocation of Intangible Assets	The following table presents details of the purchase price allocated to the acquired intangible assets at the acquisition date:
		Useful			Purchased
		Life			intangible assets
		(In years)			(In thousands)
	Developed technology	7		$	4,100
	Customer relationships	2			700
	Total purchased intangible assets			$	4,800
Pro forma Information for Business Acquisition	The unaudited pro forma results do not assume any operating efficiencies as a result of the consolidation of operations (in thousands, except per share data):
		Three Months				Three Months
		Ended March 31,				Ended March 31,
		2015				2014
	Revenue	$	81,384			$	77,705
	Net income (loss)	$	191			$	-15,064
	Basic and diluted net income (loss) per share	$	0.01			$	-0.48

Balance_Sheet_Components_Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2015
Balance Sheet Components [Abstract]
Restricted Cash and Investments	Restricted cash and investments consist of the following (See Note 8) (in thousands):
		March 31, 2015			December 31, 2014
	Restricted in connection with notes payable	$	4,006		$	3,754
	Restricted in connection with Comerica Bank term loan		—			17,500
	Total restricted cash and investments	$	4,006		$	21,254
	Reported as:
	Restricted cash and investments	$	4,006		$	5,504
	Restricted cash and investments, non-current		—			15,750
	Total restricted cash and investments	$	4,006		$	21,254
Accounts Receivable, Net	Accounts receivable, net consists of the following (in thousands):
		March 31, 2015			December 31, 2014
	Accounts receivable	$	81,347		$	69,839
	Trade notes receivable		5,587			7,999
	Allowance for doubtful accounts		(1,131	)		(241	)
		$	85,803		$	77,597
Inventories	Inventories consist of the following (in thousands):
		March 31, 2015			December 31, 2014
	Raw materials	$	27,152		$	23,804
	Work in process		15,576			13,600
	Finished goods (1)		22,001			19,943
		$	64,729		$	57,347
	-1	Finished goods inventory at customers’ vendor managed inventory locations was $8.3 million and $6.4 million as of March 31, 2015 and December 31, 2014, respectively.
Purchased Intangible Assets	Purchased intangible assets consist of the following (in thousands):
		31-Mar-15								December 31, 2014
		Gross			Accumulated			Net		Gross		Accumulated			Net
		Assets			Amortization			Assets		Assets		Amortization			Assets
	Technology and patents	$	38,181		$	(29,295	)	$	8,886	$	34,023	$	(28,402	)	$	5,621
	Customer relationships		15,456			(11,644	)		3,812		14,725		(11,176	)		3,549
	Leasehold interest		1,391			(302	)		1,089		1,386		(293	)		1,093
	Noncompete agreements		862			(862	)		—		862		(862	)		—
		$	55,890		$	(42,103	)	$	13,787	$	50,996	$	(40,733	)	$	10,263
Amortization Expense of Purchased Intangible Assets	The following table presents details of the amortization expense of the Company’s purchased intangible assets as reported in the condensed consolidated statements of operations (in thousands):
		Three Months Ended
		March 31,
		2015			2014
	Cost of goods sold	$	839		$	714
	Operating expenses		449			379
	Total	$	1,288		$	1,093
Estimated Future Amortization Expense of Purchased Intangible Assets	The estimated future amortization expense of purchased intangible assets as of March 31, 2015, is as follows (in thousands):
	2015 (remaining nine months)	$	3,862
	2016		4,465
	2017		1,328
	2018		1,151
	2019		795
	Thereafter		2,186
		$	13,787
Accrued Expenses and Other Current Liabilities	Accrued and other current liabilities consist of the following (in thousands):
		March 31, 2015			December 31, 2014
	Employee-related	$	16,216		$	13,635
	Accrued warranty		1,647			1,751
	Penalty payment derivative		530			530
	Deferred income tax liabilities		181			181
	Other		5,353			6,631
		$	23,927		$	22,728
Summary of Movement in Warranty Accrual	The table below summarizes the movement in the warranty accrual, which is included in accrued and other current liabilities (in thousands):
		Three Months Ended
		March 31,
		2015			2014
	Beginning balance	$	1,751		$	1,737
	Warranty accruals		68			289
	Settlements and adjustments		-172			(357	)
	Ending balance	$	1,647		$	1,669
Other Noncurrent Liabilities	Other noncurrent liabilities consist of the following (in thousands):
		March 31, 2015			December 31, 2014
	Pension and other employee-related	$	5,407		$	5,355
	Other		2,220			1,871
		$	7,627		$	7,226

Restructuring_Tables

Restructuring (Tables)	3 Months Ended
	Mar. 31, 2015
Restructuring And Related Activities [Abstract]
Restructuring and Related Costs	The following table summarizes activity associated with restructuring obligations during the three months ended March 31, 2015 (in thousands):
		Workforce			Facilities			Contract		Total
		Reduction						Termination
	Restructuring obligations, December 31, 2014	$	54		$	100		$	—	$	154
	Restructuring costs incurred		6			—			—		6
	Cash payments		(60	)		(30	)		—		(90	)
	Non-cash settlements and other		—			—			—		—
	Restructuring obligations, March 31, 2015	$	—		$	70		$	—	$	70

Debt_Tables

Debt (Tables)	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Components of Debt, Obligations, Weighted Average Interest Rate and Additional Fair Value Information Relating to Outstanding Debt Instruments	The table below summarizes the carrying amount and weighted average interest rate of the Company’s notes payable and long-term debt (in thousands, except percentages):
		31-Mar-15						31-Dec-14
		Carrying			Weighted			Carrying	Weighted
		Amount			Average			Amount	Average
					Interest				Interest
					Rate				Rate
	Notes payable	$	12,921		—		$	12,771	—
	Short-term borrowing		10,000		3.18	%		10,000	3.18	%
	Total notes payable and short-term borrowing	$	22,921				$	22,771
	Long-term debt, current and non-current:
	Bank borrowings-Comerica Bank	$	15,787		2.92	%	$	17,500	3.16	%
	Bank borrowings-Mitsubishi Bank		12,469		1.53	%		—	—
	Acquisition-related		15,482		5	%		5,836	1.5	%
	Total long-term debt, current and non-current		43,738					23,336
	Unaccreted discount within current portion of long-term debt		(180	)				—
	Unaccreted discount within long-term debt, net of current portion		(305	)				—
	Total long-term debt, net of unaccreted discount	$	43,253				$	23,336
	Reported as:
	Current portion of long-term debt	$	16,138				$	2,445
	Long-term debt, net of current portion		27,115					20,891
	Total long-term debt, net of unaccreted discount	$	43,253				$	23,336
Maturities of Long-term Debt	At March 31, 2015, maturities of long-term debt were as follows (in thousands):
	2015 (remaining nine months)	$	16,109
	2016		16,623
	2017		836
	2018		5,015
	2019		836
	Thereafter		4,319
		$	43,738

Japan_Pension_Plans_Tables

Japan Pension Plans (Tables)	3 Months Ended
	Mar. 31, 2015
Compensation And Retirement Disclosure [Abstract]
Periodic Pension Cost	Net periodic pension costs associated with these plans included the following components (in thousands):
		Three Months Ended
		31-Mar-15		31-Mar-14
	Service cost	$	—	$	53
	Interest cost		—		13
	Amortization		—		1
	Net periodic pension costs	$	—	$	67

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2015
Stockholders Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income, Net of Related Taxes	The components of accumulated other comprehensive income, net of related taxes, during the three months ended March 31, 2015 were as follows (in thousands):
		March 31, 2015			March 31, 2014
	Foreign currency translation adjustment	$	6,079		$	10,202
	Unrealized gains on available-for-sale securities		3			6
	Defined benefit pension plan adjustment		(71	)		1
		$	6,011		$	10,209

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Based Compensation Expense	The following table summarizes the stock-based compensation expense recognized for the three months ended March 31, 2015 and 2014 (in thousands):
		Three Months Ended March 31,
		2015				2014
	Cost of goods sold	$	370			$	330
	Research and development		493				707
	Sales and marketing		453				373
	General and administrative		740				491
		$	2,056			$	1,901
Estimated Fair Value of Certain Stock-Based Awards Using Black-Scholes-Merton Valuation Model	The Company estimated the fair value of certain stock-based awards using a Black-Scholes-Merton valuation model with the following assumptions:
			Three Months Ended March 31,
			2015		2014
	Stock options
	Weighted-average expected term (years)		5.25		5.12
	Weighted-average volatility		63%		72%
	Risk-free interest rate		1.65%		1.75%
	Expected dividends		—  %		—  %
	Stock appreciation units
	Weighted-average expected term (years)		1.91		2.15
	Weighted-average volatility		57%		59%
	Risk-free interest rate		0.25%-1.10%		0.13% – 0.78%
	Expected dividends		—  %		—  %
	ESPP
	Weighted-average expected term (years)		0.7		0.76
	Weighted-average volatility		58%		54%
	Risk-free interest rate		0.03%-0.13%		0.10 – 0.13%
	Expected dividends		—  %		—  %
Summary of Stock Option and Restricted Stock Unit Activity	The following table summarizes the Company’s stock option and RSU activity in the three months ended March 31, 2015:
		Stock Options						Restricted Stock Units
		Number of					Weighted	Number of				Weighted
		shares					average	units				average
							exercise price					grant date
												fair value
	Balance at December 31, 2014		4,899,713			$	4.07		655,729		$	6.19
	Granted		116,500				3.38		144,954			6.51
	Exercised/Converted		(4,816	)			4.19		(174,372	)		6.57
	Forfeited and canceled		(65,587	)			5.32		(12,268	)		6.18
	Balance at March 31, 2015		4,945,810			$	4.03		614,043		$	6.16

Income_Taxes_Tables

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income (Loss) before Income Taxes	The provision for income taxes is based upon the income (loss) before income taxes as follows:
		Three Months Ended March 31,
	(in thousands)	2015		2014
	Income tax provision	$	414	$	762

Basis_of_Presentation_and_Sign2

Basis of Presentation and Significant Accounting Policies - Additional Information (Detail) (Customer Concentration Risk [Member])	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Huawei Technologies [Member] | Revenue [Member]
Concentration Risk [Line Items]
Percentage of concentration of credit risk	40.00%	35.00%
Ciena Corporation [Member] | Revenue [Member]
Concentration Risk [Line Items]
Percentage of concentration of credit risk	23.00%	14.00%
Company Top Ten Customers [Member] | Revenue [Member]
Concentration Risk [Line Items]
Percentage of concentration of credit risk	90.00%	88.00%
Alcatel-Lucent SA [Member] | Revenue [Member]
Concentration Risk [Line Items]
Percentage of concentration of credit risk		13.00%
Customer One [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Percentage of concentration of credit risk	44.00%		45.00%
Customer Two [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Percentage of concentration of credit risk	16.00%		10.00%

Computation_of_Basic_and_Dilut

Computation of Basic and Diluted Net Income (Loss) per Share (Detail) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Numerator:
Net income (loss)	$100	($12,588)
Denominator:
Basic	32,780	31,610
Dilutive effect of employee stock awards	251
Diluted	33,031	31,610
Net income (loss) per share – Basic and Diluted		($0.40)

Potentially_Dilutive_Securitie

Potentially Dilutive Securities Excluded From Computation of Diluted Net Loss per Share Attributable to Common Stockholders (Detail)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities, excluded from computation of diluted net income (loss) per share	5,330	5,559
Employee Stock Options [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities, excluded from computation of diluted net income (loss) per share	4,930	3,952
Restricted Stock Units [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities, excluded from computation of diluted net income (loss) per share	400	1,134
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities, excluded from computation of diluted net income (loss) per share		469
Common Stock Warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities, excluded from computation of diluted net income (loss) per share		4

Summary_of_Cash_Cash_Equivalen

Summary of Cash, Cash Equivalents, Short-Term investments, and Restricted Cash and Investments (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Cash and cash equivalents:
Cash	$54,553	$43,035
Cash equivalents	7,449
Cash and cash equivalents	62,002	43,035	53,056	57,101
Short-term investments	8,296
Restricted cash and investments:
Restricted cash and investments, current	4,006	5,504
Restricted cash and investments, non-current		15,750
Total restricted cash and investments	$4,006	$21,254

Summary_of_Unrealized_Gains_an

Summary of Unrealized Gains and Losses Related to Cash Equivalents and Investments in Marketable Securities (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule Of Available For Sale Securities [Line Items]
Fair Value	$8,296	$8,297
Short Term Investments and Restricted Investments [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	8,293	8,291
Gross Unrealized Gains	3	6
Fair Value	8,296	8,297
Short Term Investments and Restricted Investments [Member] | Money Market Funds [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	4,585	4,587
Fair Value	4,585	4,587
Short Term Investments and Restricted Investments [Member] | Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	2,008	2,004
Gross Unrealized Gains	3	6
Fair Value	2,011	2,010
Short Term Investments and Restricted Investments [Member] | Variable Rate Demand Notes [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	1,700	1,700
Fair Value	1,700	1,700
Short-Term Investments [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	8,293
Gross Unrealized Gains	3
Fair Value	8,296
Restricted cash and investments, non-current [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		8,291
Gross Unrealized Gains		6
Fair Value		$8,297

Maturities_of_Marketable_Secur

Maturities of Marketable Securities (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value Disclosures [Abstract]
Less than 1 year	$6,596	$6,597
Due after 5 years	1,700	1,700
Fair Value	$8,296	$8,297

Cash_Cash_Equivalents_and_Shor2

Cash, Cash Equivalents and Short-Term Investments and Restricted Cash and Investments - Additional information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Fair Value Disclosures [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	$0	$0

Fair_Value_of_Financial_Assets

Fair Value of Financial Assets (Detail) (Fair Value, Measurements, Recurring [Member], USD $)	Mar. 31, 2015	Dec. 31, 2014
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	$8,296,000	$8,297,000
Fair Value, Inputs, Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	4,585,000	4,587,000
Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	3,711,000	3,710,000
Money Market Funds [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	4,585,000	4,587,000
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	4,585,000	4,587,000
Corporate Bonds [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	2,011,000	2,010,000
Corporate Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	2,011,000	2,010,000
Variable Rate Demand Notes [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	1,700,000	1,700,000
Variable Rate Demand Notes [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	1,700,000	1,700,000
Mutual Funds Held in Rabbi Trust [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	450,000	424,000
Mutual Funds Held in Rabbi Trust [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	$450,000	$424,000

Fair_Value_of_Financial_Liabil

Fair Value of Financial Liabilities (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Penalty payment derivative	$530	$530
Fair Value, Measurements, Recurring [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Penalty payment derivative	530	530
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Penalty payment derivative	$530	$530

Fair_Value_Disclosures_Additio

Fair Value Disclosures - Additional information (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Measurements, Recurring [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Transfers between levels of the fair value hierarchy, Assets	$0	$0
Transfers between levels of the fair value hierarchy, Assets	0	0
Transfers between levels of the fair value hierarchy, Liabilities	0	0
Transfers between levels of the fair value hierarchy, Liabilities	0	0
Assets measured at fair value	8,296,000	8,297,000
Fair Value, Measurements, Nonrecurring [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets measured at fair value	0	0
Liabilities measured at fair value	$0	$0

Business_Combination_Additiona

Business Combination - Additional Information (Detail) (USD $)	3 Months Ended		0 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Jan. 02, 2015	Apr. 16, 2015
Business Acquisition [Line Items]
Issuance of notes to the seller of acquired business	$15,482
Acquisition-related transaction costs	140
Goodwill	1,141
Revenue	81,384	68,168
Tunable Laser Product Lines From EMCORE Corporation [Member]
Business Acquisition [Line Items]
Total consideration	16,982		17,500
Cash consideration paid	1,500		1,500
Issuance of notes to the seller of acquired business	15,482		16,000
Acquisition-related transaction costs	800
Goodwill	1,141
EMCORE [Member] | Pro Forma [Member] | Elimination [Member]
Business Acquisition [Line Items]
Acquisition-related transaction costs	100
Revenue	0	0
Subsequent Event [Member] | Tunable Laser Product Lines From EMCORE Corporation [Member]
Business Acquisition [Line Items]
Total consideration				16,982
Issuance of notes to the seller of acquired business				$15,482

Acquisition_Accounting_and_Tan

Acquisition Accounting and Tangible and Intangible Assets Acquired (Detail) (USD $)	0 Months Ended	3 Months Ended
In Thousands, unless otherwise specified	Jan. 02, 2015	Mar. 31, 2015
Total purchase consideration:
Issuance of notes to the seller of acquired business		$15,482
Less: fair value of liabilities assumed:
Goodwill		1,141
Tunable Laser Product Lines From EMCORE Corporation [Member]
Total purchase consideration:
Cash consideration paid	1,500	1,500
Issuance of notes to the seller of acquired business	16,000	15,482
Total consideration	17,500	16,982
Fair value of assets acquired:
Accounts receivable, net of allowance for doubtful accounts		9,433
Inventories, net of inventory reserves		1,582
Prepaid expenses and other current assets		654
Property, plant and equipment		6,917
Intangible assets acquired:
Intangible assets acquired		4,800
Intangible assets acquired		23,386
Less: fair value of liabilities assumed:
Accounts payable		-7,427
Accrued liabilities		-118
Fair value of liabilities assumed total		-7,545
Goodwill		1,141
Tunable Laser Product Lines From EMCORE Corporation [Member] | Developed Technology [Member]
Intangible assets acquired:
Intangible assets acquired		4,100
Tunable Laser Product Lines From EMCORE Corporation [Member] | Customer Relationships [Member]
Intangible assets acquired:
Intangible assets acquired		$700

Acquisition_Accounting_and_Tan1

Acquisition Accounting and Tangible and Intangible Assets Acquired (Parenthetical) (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Business Acquisition [Line Items]
Allowance for doubtful accounts receivable current	$1,131	$241
Tunable Laser Product Lines From EMCORE Corporation [Member]
Business Acquisition [Line Items]
Allowance for doubtful accounts receivable current	836
Inventory valuation reserves	$616

Purchase_Price_Allocation_of_I

Purchase Price Allocation of Intangible Assets (Detail) (Tunable Laser Product Lines From EMCORE Corporation [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Business Acquisition [Line Items]
Purchased intangible assets	$4,800
Developed Technology [Member]
Business Acquisition [Line Items]
Useful Life (in years)	7 years
Purchased intangible assets	4,100
Customer Relationships [Member]
Business Acquisition [Line Items]
Useful Life (in years)	2 years
Purchased intangible assets	$700

Pro_forma_Information_for_Busi

Pro forma Information for Business Acquisition (Detail) (EMCORE [Member], USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
EMCORE [Member]
Business Acquisition Pro Forma Information Nonrecurring Adjustment [Line Items]
Revenue	$81,384	$77,705
Net income (loss)	$191	($15,064)
Basic and diluted net income (loss) per share	$0.01	($0.48)

Restricted_Cash_and_Investment

Restricted Cash and Investments (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Restricted Cash And Cash Equivalents Items [Line Items]
Restricted in connection with notes payable	$4,006	$21,254
Total restricted cash and investments	4,006	21,254
Restricted cash and investments	4,006	5,504
Restricted cash and investments, non-current		15,750
Notes Payable [Member]
Restricted Cash And Cash Equivalents Items [Line Items]
Restricted in connection with notes payable	4,006	3,754
Total restricted cash and investments	4,006	3,754
Restricted cash and investments	4,000	3,800
Comerica Bank Term Loan [Member]
Restricted Cash And Cash Equivalents Items [Line Items]
Restricted in connection with notes payable		17,500
Total restricted cash and investments		$17,500

Accounts_Receivable_Net_Detail

Accounts Receivable, Net (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Receivables [Abstract]
Accounts receivable	$81,347	$69,839
Trade notes receivable	5,587	7,999
Allowance for doubtful accounts	-1,131	-241
Accounts receivable, Net ,Total	$85,803	$77,597

Inventory_Detail

Inventory (Detail) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]
Raw materials	$27,152		$23,804
Work in process	15,576		13,600
Finished goods	22,001	[1]	19,943	[1]
Inventories	$64,729		$57,347
[1]	Finished goods inventory at customers’ vendor managed inventory locations was $8.3 million and $6.4 million as of March 31, 2015 and December 31, 2014, respectively.

Inventory_Parenthetical_Detail

Inventory (Parenthetical) (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Inventory Disclosure [Abstract]
Finished goods, at vendor managed inventory locations	$8.30	$6.40

Purchased_Intangible_Assets_De

Purchased Intangible Assets (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Finite Lived Intangible Assets [Line Items]
Gross Assets	$55,890	$50,996
Accumulated Amortization	-42,103	-40,733
Net Assets	13,787	10,263
Technology and Patents [Member]
Finite Lived Intangible Assets [Line Items]
Gross Assets	38,181	34,023
Accumulated Amortization	-29,295	-28,402
Net Assets	8,886	5,621
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross Assets	15,456	14,725
Accumulated Amortization	-11,644	-11,176
Net Assets	3,812	3,549
Leasehold Interest [Member]
Finite Lived Intangible Assets [Line Items]
Gross Assets	1,391	1,386
Accumulated Amortization	-302	-293
Net Assets	1,089	1,093
Noncompete agreements [Member]
Finite Lived Intangible Assets [Line Items]
Gross Assets	862	862
Accumulated Amortization	($862)	($862)

Amortization_Expense_of_Compan

Amortization Expense of Company's Purchased Intangible Assets (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Cost of goods sold	$839	$714
Operating expenses	449	379
Total	$1,288	$1,093

Estimated_Future_Amortization_

Estimated Future Amortization Expense of Purchased Intangible Assets (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Goodwill And Intangible Assets Disclosure [Abstract]
2015 (remaining nine months)	$3,862
2016	4,465
2017	1,328
2018	1,151
2019	795
Thereafter	2,186
Net Assets	$13,787	$10,263

Accrued_and_Other_Current_Liab

Accrued and Other Current Liabilities (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accounts Payable And Accrued Liabilities Current [Abstract]
Employee-related	$16,216	$13,635
Accrued warranty	1,647	1,751	1,669	1,737
Penalty payment derivative	530	530
Deferred income tax liabilities	181	181
Other	5,353	6,631
Accrued and other current liabilities	$23,927	$22,728

Summary_of_Movement_in_Warrant

Summary of Movement in Warranty Accrual (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Accounting Policies [Abstract]
Beginning balance	$1,751	$1,737
Warranty accruals	68	289
Settlements and adjustments	-172	-357
Ending balance	$1,647	$1,669

Other_Noncurrent_Liabilities_D

Other Noncurrent Liabilities (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Payables And Accruals [Abstract]
Pension and other employee-related	$5,407	$5,355
Other	2,220	1,871
Other noncurrent liabilities	$7,627	$7,226

Summary_of_Restructuring_Activ

Summary of Restructuring Activity (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Restructuring Cost And Reserve [Line Items]
Restructuring obligations, beginning balance	$154
Restructuring costs incurred	6
Cash payments	-90
Restructuring obligations, ending balance	70
Workforce Reduction [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring obligations, beginning balance	54
Restructuring costs incurred	6
Cash payments	-60
Facilities [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring obligations, beginning balance	100
Cash payments	-30
Restructuring obligations, ending balance	$70

Components_of_Debt_Obligations

Components of Debt, Obligations, Weighted Average Interest Rate and Additional Fair Value Information Relating to Outstanding Debt Instruments (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Notes payable, carrying amount	$22,921	$22,771
Long-term debt, carrying amount	43,738	23,336
Unaccreted discount within current portion of long-term debt, carrying amount	-180
Unaccreted discount within long-term debt, net of current portion, carrying amount	-305
Total long-term debt, net of unaccreted discount	43,253	23,336
Current portion of long-term debt	16,138	2,445
Long-term debt, net of current portion	27,115	20,891
Notes Payable [Member]
Debt Instrument [Line Items]
Notes payable, carrying amount	12,921	12,771
Short Term Borrowing [Member]
Debt Instrument [Line Items]
Notes payable, carrying amount	10,000	10,000
Notes payable, carrying amount	3.18%	3.18%
Bank Borrowings [Member] | Comerica Bank [Member]
Debt Instrument [Line Items]
Long-term debt, carrying amount	15,787	17,500
Notes payable, carrying amount	2.92%	3.16%
Bank Borrowings [Member] | Mitsubishi Bank [Member]
Debt Instrument [Line Items]
Long-term debt, carrying amount	12,469
Notes payable, carrying amount	1.53%
NeoPhotonics Semiconductor [Member]
Debt Instrument [Line Items]
Long-term debt, carrying amount	$15,482	$5,836
Notes payable, carrying amount	5.00%	1.50%

Debt_Additional_Information_De

Debt - Additional Information (Detail)

3 Months Ended

0 Months Ended

3 Months Ended

0 Months Ended

3 Months Ended

3 Months Ended

0 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

3 Months Ended

0 Months Ended

0 Months Ended

0 Months Ended

0 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

Mar. 31, 2015

Mar. 31, 2014

Dec. 31, 2014

Feb. 25, 2015

Feb. 25, 2015

Mar. 31, 2015

Feb. 25, 2015

Feb. 25, 2015

Feb. 25, 2015

Feb. 25, 2015

Mar. 31, 2015

Dec. 31, 2014

Mar. 31, 2015

Mar. 31, 2015

Jan. 02, 2015

Jan. 31, 2015

Mar. 31, 2015

Jan. 31, 2015

Jan. 31, 2015

Jan. 31, 2015

Mar. 31, 2015

Mar. 31, 2015

Mar. 31, 2015

Mar. 31, 2015

Sep. 30, 2014

Sep. 30, 2014

Mar. 31, 2015

Dec. 31, 2014

Mar. 31, 2015

Mar. 31, 2015

Mar. 31, 2015

Jan. 31, 2015

Mar. 31, 2015

Jan. 31, 2015

Jan. 31, 2015

Jan. 31, 2015

Mar. 31, 2015

Mar. 31, 2015

Mar. 31, 2015

Mar. 31, 2015

Mar. 31, 2015

Dec. 31, 2014

Mar. 31, 2015

Mar. 31, 2015

Dec. 31, 2014

Dec. 31, 2014

Mar. 29, 2013

Oct. 31, 2014

Mar. 31, 2015

Nov. 30, 2014

Mar. 31, 2015

USD ($)

USD ($)

USD ($)

Mitsubishi Bank [Member]

Mitsubishi Bank [Member]

Mitsubishi Bank [Member]

Mitsubishi Bank [Member]

Mitsubishi Bank [Member]

Mitsubishi Bank [Member]

Mitsubishi Bank [Member]

Bank Borrowings [Member]

Bank Borrowings [Member]

Bank Borrowings [Member]

Bank Borrowings [Member]

Tunable Laser Product Lines From EMCORE Corporation [Member]

Tunable Laser Product Lines From EMCORE Corporation [Member]

Tunable Laser Product Lines From EMCORE Corporation [Member]

Tunable Laser Product Lines From EMCORE Corporation [Member]

Tunable Laser Product Lines From EMCORE Corporation [Member]

Tunable Laser Product Lines From EMCORE Corporation [Member]

China

First Credit Facility [Member]

First Credit Facility [Member]

First Credit Facility [Member]

Second Credit Facility [Member]

Second Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Senior Secured Revolving Credit Facility [Member]

Senior Secured Revolving Credit Facility [Member]

Senior Secured Revolving Credit Facility [Member]

Senior Secured Revolving Credit Facility [Member]

Senior Secured Revolving Credit Facility [Member]

Bank Overdrafts

Bank Overdrafts

Loans Payable

Loans Payable

Notes Payable [Member]

Notes Payable [Member]

Notes Payable [Member]

Notes Payable [Member]

Notes Payable [Member]

Notes Payable [Member]

Notes Payable [Member]

First Short-Term Advance Financing Agreement

First Short-Term Advance Financing Agreement

Second Short-Term Advance Financing Agreement

Second Short-Term Advance Financing Agreement

Term Loan B [Member]

Term Loan B [Member]

Term Loan B [Member]

Term Loan B [Member]

Term Loan A [Member]

Term Loan A [Member]

Term Loan A [Member]

USD ($)

USD ($)

Credit Facility Base Rate [Member]

Libor Plus Rate [Member]

USD ($)

USD ($)

First Year [Member]

Second Year [Member]

Mitsubishi Bank [Member]

USD ($)

China

China

China

China

China

USD ($)

USD ($)

Comerica [Member]

Credit Facility Base Rate [Member]

Libor Plus Rate [Member]

Comerica [Member]

Comerica [Member]

Credit Facility Base Rate [Member]

Libor Plus Rate [Member]

First Credit Facility [Member]

First Credit Facility [Member]

First Credit Facility [Member]

First Credit Facility [Member]

USD ($)

USD ($)

NeoPhotonics Semiconductor [Member]

NeoPhotonics Semiconductor [Member]

NeoPhotonics Semiconductor [Member]

NeoPhotonics Semiconductor [Member]

NeoPhotonics Semiconductor [Member]

China

China

China

China

USD ($)

JPY (¥)

Tokyo Interbank Offer Rate [Member]

USD ($)

JPY (¥)

Tokyo Interbank Offer Rate [Member]

Term Loan B [Member]

Minimum [Member]

Maximum [Member]

USD ($)

CNY

USD ($)

USD ($)

USD ($)

China

China

China

China

USD ($)

JPY (¥)

USD ($)

JPY (¥)

Notes Payable To be paid in three equal installments [Member]

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

CNY

USD ($)

CNY

JPY (¥)

Debt Instrument [Line Items]

Credit facility, expiration date

30-Jun-15

30-Sep-15

30-Sep-15

Notes payable, carrying amount

$26,100,000

160,000,000

$19,600,000

120,000,000

$5,000,000

$5,000,000

Percentage of compensating balance requirement for bank acceptance drafts

25.00%

30.00%

30.00%

30.00%

Short-term line of credit facility

0

17,500,000

12,900,000

24,500,000

150,000,000

15,800,000

0

15,800,000

5,000,000

5,000,000

Restricted cash and investments

4,006,000

5,504,000

4,000,000

3,800,000

Obligation bear interest

1.50%

1.50%

4.02%

2.33%

Due date of the principal

25-Feb-25

25-Feb-25

23-Feb-18

23-Feb-18

2-Nov-16

30-Apr-15

30-Apr-15

31-May-15

Service fees

1.00%

Issuance of notes to the seller of acquired business

15,482,000

16,000,000

15,482,000

15,500,000

1,050,000,000

Notes payable outstanding

5,800,000

700,000,000

Debt Instrument, Term

2 years

Note payable, interest rate

5.00%

13.00%

Line of Credit Facility, Maximum Borrowing Capacity

20,000,000

30,000,000

25,000,000

Debt Instrument, Basis Spread on Variable Rate

1.40%

1.40%

2.00%

3.00%

1.75%

2.75%

1.75%

2.75%

Line of Credit Facility, Remaining Borrowing Capacity

30,000,000

Interest rate description

borrowings under the term loan bore interest at an interest rate option of a base rate as defined in the agreement plus 2.0% or LIBOR plus 3.0%.

bear interest at an interest rate option of a base rate as defined in the agreement plus 1.75% or LIBOR plus 2.75%. As of March 31, 2015 the rate on the LIBOR option was 2.92%.

Line of credit facility, interest rate

2.92%

Line of credit facility, expiration date

2017-06

2016-03

Debt, aggregate principal amount

8,400,000

1,000,000,000

4,200,000

500,000,000

Frequency of periodic payment

monthly

Debt, periodic principal payments

8,333,000

Debt, lump sum payment on the maturity date

8,373,000

Loan structuring fee including consumption tax

300,000

40,500,000

Repayment of notes payable

5,478,000

4,448,000

6,000,000

710,000,000

Debt Instrument, Covenant Compliance

The Company’s original credit agreement with Comerica Bank required the maintenance of specified financial covenants, including a debt to EBITDA ratio and liquidity ratios.

Restricted in connection with notes payable

$4,006,000

$21,254,000

$0

$17,500,000

$4,006,000

$3,754,000

Maturities_of_Long_Term_debt_O

Maturities of Long -Term debt Outstanding (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Maturities Of Long Term Debt [Abstract]
2015 (remaining nine months)	$16,109
2016	16,623
2017	836
2018	5,015
2019	836
Thereafter	4,319
Long Term Debt	$43,738	$23,336

Japan_Pension_Plans_Additional

Japan Pension Plans - Additional Information (Detail) (USD $)	2 Months Ended	3 Months Ended
	Feb. 28, 2014	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	31-May-14	Mar. 29, 2013
						CompensationPlan
Compensation And Retirement Disclosure [Abstract]
Number of Defined Benefit Pension Plans						2
Plan assets					$2,000,000
Conversion of plan, proceed from LAPIS		300,000
Defined Benefit Plan, Curtailments			100,000
Pension liability		5,100,000		5,100,000
Employer contributions	$15,000

Periodic_Pension_Cost_Detail

Periodic Pension Cost (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Compensation And Retirement Disclosure [Abstract]
Service cost	$53
Interest cost	13
Amortization	1
Net periodic pension costs	$67

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail)

0 Months Ended

3 Months Ended

Mar. 31, 2015

Mar. 23, 2015

Mar. 23, 2015

Sep. 16, 2013

Apr. 27, 2012

5-May-10

Mar. 31, 2015

Mar. 31, 2014

Dec. 31, 2014

Mar. 31, 2015

Mar. 31, 2015

Mar. 31, 2015

Mar. 31, 2015

Mar. 31, 2015

Mar. 31, 2015

USD ($)

USD ($)

EUR (€)

USD ($)

USD ($)

Defendant

USD ($)

USD ($)

USD ($)

Embedded Derivative Financial Instruments [Member]

Private Placement [Member]

Private Placement [Member]

Private Placement [Member]

Private Placement [Member]

Private Placement [Member]

Maximum [Member]

Embedded Derivative Financial Instruments [Member]

RUSSIAN FEDERATION

Capital Addition Purchase Commitments [Member]

General Working Capital and Research and Development Arrangement [Member]

Performance Guarantee [Member]

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Loss Contingencies [Line Items]

Number of defendants

4

Agreement period not to refile claims

90 days

Partial settlement of claims payment

$492,000

Settlement awarded amount

1,100,000

1,000,000

Probable or reasonably possible loss

0

0

Operating Leases, Future Minimum Payments Due

7,500,000

7,500,000

Rent expense

500,000

500,000

Other non-current liability

5,000,000

15,000,000

30,000,000

Other current liability, cash and non-cash

15,000,000

Percentage of investment obligation that must be spent inside Russia

80.00%

Proceeds from issuance of common stock, net of issuance costs

39,800,000

Operating investment commitment completion

33.00%

Operating investment purchase commitment period

5 years

Securities lock up agreement period

60 days

Additional paid-in capital

4,900,000

Penalty payment derivative

$530,000

$530,000

$530,000

$100,000

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Class Of Stock [Line Items]
Realized gains on available-for-sale securities	$0	$0
Accumulated deficit subject to restriction			$7.10
Accumulated profits			10.00%
Employee Stock Options [Member]
Class Of Stock [Line Items]
Common stock	7,424,305
Employee Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Common stock	978,382

Schedule_of_Accumulated_Other_

Schedule of Accumulated Other Comprehensive Income, Net of Related Taxes (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
In Thousands, unless otherwise specified
Stockholders Equity Note [Abstract]
Foreign currency translation adjustment	$6,079		$10,202
Unrealized gains on available-for-sale securities	3		6
Defined benefit pension plan adjustment	-71		1
Accumulated other comprehensive income, Net of tax	$6,011	$5,326	$10,209

Summary_of_StockBased_Compensa

Summary of Stock-Based Compensation Expense (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$2,056	$1,901
Cost of Goods Sold [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	370	330
Research and Development Expense [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	493	707
Selling and Marketing Expense [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	453	373
General and Administrative Expense [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$740	$491

Estimated_Fair_Value_of_Certai

Estimated Fair Value of Certain Stock-Based Awards Using Black-Scholes-Merton Valuation Model (Detail)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Employee Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average expected term (years)	5 years 3 months	5 years 1 month 13 days
Weighted-average volatility	63.00%	72.00%
Risk-free interest rate	1.65%	1.75%
Expected dividends	0.00%	0.00%
Stock Appreciation Units (SARs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average expected term (years)	1 year 10 months 28 days	2 years 1 month 24 days
Weighted-average volatility	57.00%	59.00%
Expected dividends	0.00%	0.00%
Risk-free interest rate Minimum	0.25%	0.13%
Risk-free interest rate Maximum	1.10%	0.78%
Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average expected term (years)	8 months 12 days	9 months 4 days
Weighted-average volatility	58.00%	54.00%
Expected dividends	0.00%	0.00%
Risk-free interest rate Minimum	0.03%	0.10%
Risk-free interest rate Maximum	0.13%	0.13%

Summary_of_Stock_Option_and_Re

Summary of Stock Option and Restricted Stock Unit Activity (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015
Employee Stock Options [Member]
Number of Shares
Beginning Balance	4,899,713
Granted	116,500
Exercised/Converted	-4,816
Forfeited and canceled	-65,587
Ending Balance	4,945,810
Weighted Average Exercise Price
Beginning Balance	$4.07
Granted	$3.38
Exercised/Converted	$4.19
Forfeited and canceled	$5.32
Ending Balance	$4.03
Restricted Stock Units [Member]
Number of Shares
Granted	139,954
Number of Units
Beginning Balance	655,729
Granted	144,954
Exercised/Converted	-174,372
Forfeited and canceled	-12,268
Ending Balance	614,043
Weighted Average Exercise Price
Beginning Balance	$6.19
Granted	$6.51
Exercised/Converted	$6.57
Forfeited and canceled	$6.18
Ending Balance	$6.16

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock grants granted, shares	139,954
Stock grants vested value	$0.90
Shares outstanding	614,043	655,729
Stock Appreciation Units (SARs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares outstanding	368,995		375,833
Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation cost, net of forecasted forfeitures	$0.30

Components_of_Provision_for_In

Components of Provision for Income Taxes (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Income Tax Disclosure [Abstract]
Income tax provision	$414	$762

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (State Administration of Taxation China [Member], Subsidiaries [Member])	3 Months Ended
	Mar. 31, 2015
State Administration of Taxation China [Member] | Subsidiaries [Member]
Income Taxes [Line Items]
Effective income tax rate	15.00%
Income tax statutory rate	25.00%

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (USD $)	3 Months Ended	1 Months Ended	0 Months Ended
	Mar. 31, 2015	Oct. 31, 2014	Apr. 23, 2015	Apr. 21, 2015	Apr. 16, 2015	Dec. 31, 2014
Subsequent Event [Line Items]
Issuance of notes to the seller of acquired business	$15,482,000
Notes payable, carrying amount	22,921,000					22,771,000
First Short-Term Advance Financing Agreement | China
Subsequent Event [Line Items]
Due date of the principal and interest	8-Oct-15
Due date of the principal	30-Apr-15	30-Apr-15
Adjusted LIBOR variable rate term	6 months
First Short-Term Advance Financing Agreement | China | Libor Plus Rate [Member]
Subsequent Event [Line Items]
Debt instrument description of variable rate basis	LIBOR
Subsequent Event [Member] | First Short-Term Advance Financing Agreement | China
Subsequent Event [Line Items]
Notes payable, carrying amount				5,000,000
Debt Instrument, Basis Spread on Variable Rate				3.30%
Repayment of line of credit facility			5,000,000
Subsequent Event [Member] | First Short-Term Advance Financing Agreement | China | Libor Plus Rate [Member]
Subsequent Event [Line Items]
Obligation bear interest				3.71%
Subsequent Event [Member] | True Up Agreement by EMCORE Corporation [Member] | Maximum [Member]
Subsequent Event [Line Items]
Issuance of notes to the seller of acquired business					16,000,000
Subsequent Event [Member] | True Up Agreement by EMCORE Corporation [Member] | Minimum [Member]
Subsequent Event [Line Items]
Issuance of notes to the seller of acquired business					$15,500,000