Stamps.com (STMP) 10-K 1 Mar 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Jan. 31, 2017	Jun. 30, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	STAMPS.COM INC
Entity Central Index Key	1,082,923
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 1,378,980,564
Entity Common Stock, Shares Outstanding		16,847,816
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 106,932	$ 65,126
Short-term investments	1,511	8,553
Accounts receivable, net	62,756	55,052
Other current assets	13,081	8,345
Total current assets	184,280	137,076
Property and equipment, net	36,829	31,707
Goodwill	239,705	197,807
Intangible assets, net	97,027	95,950
Long-term investments	0	1,529
Deferred income taxes, net	48,782	57,224
Other assets	3,506	7,321
Total assets	610,129	528,614
Current liabilities:
Accounts payable and accrued expenses	86,205	60,816
Deferred revenue	3,858	4,000
Current portion of debt, net of debt issuance costs	6,329	4,267
Contingent consideration	0	63,209
Total current liabilities	96,392	132,292
Long-term debt, net of debt issuance costs	141,025	157,353
Total liabilities	237,417	289,645
Commitments and contingencies
Stockholders' equity:
Common stock, $.001 par value Authorized shares: 47,500 in 2016 and 2015 Issued shares: 30,507 in 2016 and 29,463 in 2015 Outstanding shares: 16,897 in 2016 and 16,697 in 2015	53	52
Additional paid-in capital	855,344	716,253
Treasury stock, at cost, 13,610 shares in 2016 and 12,766 in 2015	(252,981)	(172,410)
Accumulated deficit	(229,715)	(304,944)
Accumulated other comprehensive income	11	18
Total stockholders' equity	372,712	238,969
Total liabilities and stockholders' equity	$ 610,129	$ 528,614

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares shares in Thousands	Dec. 31, 2016	Dec. 31, 2015
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	47,500	47,500
Common stock shares issued (in shares)	30,507	29,463
Common stock shares outstanding (in shares)	16,897	16,697
Treasury stock, shares (in shares)	13,610	12,766

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Revenues:
Service	$ 313,057	$ 176,672		$ 115,696
Product	20,234	18,283		16,883
Insurance	17,300	11,732		9,217
Customized postage	13,615	7,229		5,450
Other	99	41		23
Total revenues	364,305	213,957		147,269
Cost of revenues (exclusive of amortization of intangible assets, which is included in general and administrative expense):
Service	39,999	27,967		19,687
Product	6,695	5,971		5,516
Insurance	5,432	3,984		3,210
Customized postage	10,846	6,013		4,493
Total cost of revenues	62,972	43,935		32,906
Gross profit	301,333	170,022		114,363
Operating expenses:
Sales and marketing	78,830	56,144		43,659
Research and development	35,158	20,711		13,309
General and administrative	67,125	42,399		25,147
Contingent consideration charges	0	46,088		8,438
Litigation settlement	0	10,000		0
Total operating expenses	181,113	175,342		90,553
Income (loss) from operations	120,220	(5,320)		23,810
Interest expense	(3,552)	(397)		0
Interest and other income	306	146		375
Income (loss) before income taxes	116,974	(5,571)		24,185
Income tax expense (benefit)	41,745	(1,373)		(12,697)
Net income (loss)	$ 75,229	$ (4,198)		$ 36,882
Net income (loss) per share
Basic (in dollars per share)	$ 4.36	$ (0.26)		$ 2.30
Diluted (in dollars per share)	$ 4.12	$ (0.26)		$ 2.25
Weighted average shares outstanding
Basic (in shares)	17,245	16,436		16,011
Diluted (in shares)	18,251	16,436	[1]	16,417
[1]	Common equivalent shares are excluded from the diluted loss per share as their effect is anti-dilutive.

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) [Abstract]
Net income (loss)	$ 75,229	$ (4,198)	$ 36,882
Other comprehensive loss, net of tax:
Unrealized loss on investments	(7)	(43)	(79)
Comprehensive income (loss)	$ 75,222	$ (4,241)	$ 36,803

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock at Cost [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2013	$ 51	$ 668,724	$ (159,522)	$ (337,628)	$ 140	$ 171,765
Balance (in shares) at Dec. 31, 2013	16,187
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 0	0	0	36,882	0	36,882
Unrealized loss on investments	0	0	0	0	(79)	(79)
Stock-based compensation expense	0	4,799	0	0	0	4,799
Exercise of stock options	$ 0	3,314	0	0	0	$ 3,314
Exercise of stock options (in shares)	203					203
Shares issued under the Employee Stock Purchase Plan	$ 0	1,238	0	0	0	$ 1,238
Shares issued under the Employee Stock Purchase Plan (in shares)	42
Stock repurchase	$ 0	0	(12,888)	0	0	(12,888)
Stock repurchase (in shares)	(435)
Balance at Dec. 31, 2014	$ 51	678,075	(172,410)	(300,746)	61	205,031
Balance (in shares) at Dec. 31, 2014	15,997
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 0	0	0	(4,198)	0	(4,198)
Unrealized loss on investments	0	0	0	0	(43)	(43)
Stock option windfall tax benefit	0	618	0	0	0	618
Issuance of shares for contingent consideration	$ 0	9,225	0	0	0	9,225
Issuance of shares for contingent consideration (in shares)	192
Stock-based compensation expense	$ 0	15,895	0	0	0	15,895
Exercise of stock options	$ 1	10,886	0	0	0	$ 10,887
Exercise of stock options (in shares)	459					459
Shares issued under the Employee Stock Purchase Plan	$ 0	1,554	0	0	0	$ 1,554
Shares issued under the Employee Stock Purchase Plan (in shares)	49
Balance at Dec. 31, 2015	$ 52	716,253	(172,410)	(304,944)	18	$ 238,969
Balance (in shares) at Dec. 31, 2015	16,697					16,697
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 0	0	0	75,229	0	$ 75,229
Unrealized loss on investments	0	0	0	0	(7)	(7)
Stock option windfall tax benefit	0	26,784	0	0	0	26,784
Issuance of shares for contingent consideration	$ 1	63,208	0	0	0	63,209
Issuance of shares for contingent consideration (in shares)	577
Stock-based compensation expense	$ 0	33,949	0	0	0	33,949
Stock-based compensation expense (in shares)	0
Exercise of stock options	$ 0	12,969	0	0	0	$ 12,969
Exercise of stock options (in shares)	432					432
Shares issued under the Employee Stock Purchase Plan	$ 0	2,181	0	0	0	$ 2,181
Shares issued under the Employee Stock Purchase Plan (in shares)	35
Stock repurchase	$ 0	0	(80,571)	0	0	(80,571)
Stock repurchase (in shares)	(844)
Balance at Dec. 31, 2016	$ 53	$ 855,344	$ (252,981)	$ (229,715)	$ 11	$ 372,712
Balance (in shares) at Dec. 31, 2016	16,897					16,897

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities:
Net income (loss)	$ 75,229	$ (4,198)	$ 36,882
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	19,152	7,702	4,833
Loss on disposal of assets	22	0	0
Stock-based compensation expense	33,949	15,895	4,799
Deferred income tax expense (benefit)	33,623	(3,408)	(13,554)
Stock option windfall tax benefit	(26,784)	(618)	0
Accretion of debt issuance costs	372	31	0
Contingent consideration	0	47,419	8,773
Changes in operating assets and liabilities, net of assets and liabilities acquired:
Accounts receivable	(6,510)	(32,480)	5,787
Other current assets	(4,761)	(1,737)	557
Other assets	3,815	678	(3,208)
Deferred revenue	(195)	779	210
Accounts payable and accrued expenses	20,135	16,053	6,646
Net cash provided by operating activities	148,047	46,116	51,725
Investing activities:
Sale of short-term investments	8,484	6,424	6,556
Purchase of short-term investments	0	(2,438)	(6,536)
Sale of long-term investments	95	2,586	6,627
Purchase of long-term investments	(15)	0	(2,887)
Acquisition of ShipStation, net of cash acquired	0	0	(48,883)
Acquisition of ShipWorks, net of cash acquired	0	0	(21,149)
Acquisition of Endicia	(573)	(214,165)	0
Acquisition of ShippingEasy	(55,447)	0	0
Acquisition of property and equipment	(7,750)	(2,291)	(2,858)
Net cash used in investing activities	(55,206)	(209,884)	(69,130)
Financing activities:
Proceeds from short term financing obligation, net of repayments	2,241	13,313	0
Proceeds from debt, net of debt issuance cost	0	162,620	0
Principal payments on term loan	(4,639)	(1,031)	0
Payment on revolving credit facility	(10,000)	0	0
Proceeds from exercise of stock options	12,969	10,887	3,314
Issuance of common stock under Employee Stock Purchase Plan	2,181	1,554	1,238
Stock option windfall tax benefit	26,784	618	0
Repurchase of common stock	(80,571)	0	(12,888)
Net cash provided by (used in) financing activities	(51,035)	187,961	(8,336)
Net increase (decrease) in cash and cash equivalents	41,806	24,193	(25,741)
Cash and cash equivalents at beginning of period	65,126	40,933	66,674
Cash and cash equivalents at end of period	106,932	65,126	40,933
Supplemental Information:
Capital expenditures accrued but not paid at period end	1,250	78	6
Tenant improvement allowance	676	0	0
Income taxes paid	4,832	956	856
Interest paid	2,856	0	0
Issuance of 2015 and 2014 earn-out shares (see Note -3 "Acquisitions")	63,209	9,225	0
Non cash adjustment of purchase price allocation for Endicia acquisition	372	0	0
Non cash adjustment of purchase price allocation for ShippingEasy acquisition	$ 173	$ 0	$ 0

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2016
Description of Business [Abstract]
Description of Business	1. Description of Business Stamps.com® is a leading provider of Internet-based mailing and shipping solutions in the United States. Under the Stamps.com and Endicia brands, customers use our United States Postal Service (“USPS”) only solutions to mail and ship a variety of mail pieces and packages through the USPS. Customers using our solutions receive discounted postage rates compared to USPS.com and USPS retail locations on certain mail pieces such as First Class letters and domestic and international Priority Mail® and Priority Mail Express® packages. Stamps.com was the first ever to offer a software only mailing and shipping solution in 1999. Endicia became a USPS-approved PC Postage vendor in 2000. Under the ShipStation®, ShipWorks® and ShippingEasy TM brands, customers use our multi-carrier solutions to ship packages through multiple carriers such as the USPS, UPS, FedEx and others. Our customers include individuals, small businesses, home offices, medium-size businesses, large enterprises, e-commerce merchants and warehouse shippers.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Summary of Significant Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Principles of Consolidation The consolidated financial statements include the accounts of Stamps.com Inc., Auctane LLC, Interapptive, Inc., PSI Systems Inc., ShippingEasy Group, Inc., and PhotoStamps Inc. In June 2014, we completed our acquisition of 100% of the outstanding equity of Auctane LLC, a Texas limited liability company that operates ShipStation (“Auctane LLC” or “ShipStation”) in a cash and contingent stock transaction. ShipStation, based in Austin, Texas, offers web-based multi-carrier shipping solutions primarily under the brands ShipStation and Auctane. In August 2014, we completed our acquisition of 100% of the outstanding equity of Interapptive, Inc., a Missouri corporation, that operates ShipWorks (“Interapptive, Inc.” or “ShipWorks”) in a cash transaction. ShipWorks, based in St. Louis, Missouri, offers software-based multi-carrier shipping solutions. In November 2015, we completed our acquisition of 100% of the outstanding shares of PSI Systems, Inc. (“Endicia”). Endicia, based in Mountain View, California, offers mailing and shipping solutions for use with the USPS. In July 2016, we completed our acquisition of 100% of the outstanding shares of ShippingEasy Group, Inc. (“ShippingEasy”). ShippingEasy, based in Austin, Texas, offers web-based multi-carrier shipping solutions. See Note 3 – “Acquisitions” Because 100% of the voting control of Auctane LLC, Interapptive, Inc., PSI Systems, Inc., and ShippingEasy Group, Inc. is held by us, we have consolidated the results of operations of ShipStation, ShipWorks, Endicia and ShippingEasy from the date we obtained control in the accompanying consolidated financial statements. Similarly, due to our 100% control of PhotoStamps, Inc., PhotoStamps Inc. is also consolidated in the accompanying consolidated financial statements from the date of its inception. All significant intercompany accounts and transactions have been eliminated. Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles (“US GAAP”) requires us to make estimates and assumptions that affect the amounts reported in the financial statements and the accompanying notes. Actual results could differ from those estimates, and such differences may be material to the financial statements. Examples include estimates of loss contingencies, realizability of deferred income taxes, the estimates and assumptions used to calculate stock-based compensation, the estimates and assumptions used to calculate the allocation of the purchase price related to our acquisitions, including related contingent consideration, and estimates regarding the useful lives of our building, patents and other amortizable intangible assets, and goodwill. Accounts Receivable Our accounts receivable relate to mailing and shipping services, postage purchasing and invoicing, PhotoStamps sales, and branded insurance provided to customers prior to billing and other receivables. Accounts receivable are recorded at the invoiced amount, net of allowances for uncollectible accounts of approximately $1,188,000, $831,000 and $414,000 as of December 31, 2016, 2015 and 2014, respectively. We evaluate the collectability of our accounts receivable based on a combination of factors. If we become aware of a customer’s inability to meet its financial obligations, an allowance is recorded to reduce the net receivable to the amount reasonably believed to be collectible from the customer. For all other customers, we recognize allowances for doubtful accounts based on the length of time the receivables are past due, the current business environment and our historical experience. If the financial condition of our customers deteriorates, resulting in their inability to make payments, additional provisions are recorded in that period. Accounts receivable are written off against the allowance for uncollectible accounts when we determine amounts are no longer collectible. Increases in allowance for doubtful accounts totaled approximately $356,000, $417,000 and $131,000 for 2016, 2015 and 2014, respectively. There were no material write offs against the allowance for doubtful accounts during 2016, 2015 or 2014. Advertising Costs We expense the costs of producing advertisements as incurred, and expense the costs of communicating and placing the advertising in the period in which the advertising space or airtime is used. For the years ended December 31, 2016, 2015 and 2014, advertising and tradeshow costs were $12.1 million, $10.8 million and $9.7 million, respectively. Business Combinations The acquisition method of accounting is used for business combinations. The results of operations of acquired businesses are included in our consolidated financial statements prospectively from the date of acquisition. The fair value of purchase consideration is allocated to the assets acquired and liabilities assumed from the acquired entity and is generally based on their fair value at the acquisition date. The excess of the fair value of purchase consideration over the fair value of the assets acquired and liabilities assumed is recorded as goodwill. Historically the primary items that have generated goodwill include anticipated synergies between the acquired business and the Company and the acquired assembled workforce, neither of which qualifies for recognition as an intangible asset. Acquisition-related expenses are recognized in our consolidated financial statements as incurred. Contingencies and Litigation We are subject to various routine litigation matters as a claimant and a defendant. We record any amounts recovered in these matters when received. We establish loss provisions for claims against us when the loss is both probable and can be reasonably estimated. If either or both of the criteria are not met, we assess whether there is at least a reasonable possibility that a loss, or additional losses, may have been incurred. If there is a reasonable possibility that a loss or additional loss may have been incurred for such proceedings, we disclose the estimate of the amount of loss or possible range of loss, or disclose that an estimate of loss cannot be made, as applicable. Cash Equivalents and Investments We consider all highly liquid investments with an original or remaining maturity of three months or less at the date of purchase to be cash equivalents. Our cash equivalents and investments consisted of money market funds, asset-backed securities and public corporate debt securities at December 31, 2016 and 2015. All investments are classified as available for sale and are recorded at market value using the specific identification method. Realized gains and losses are reflected in interest and other income, net while unrealized gains and losses are included as a separate component of stockholders' equity. Concentration of Risk Our cash, cash equivalents and investments are subject to market risk, primarily interest rate and credit risk. Our investments are managed by a limited number of outside professional managers within investment guidelines set by us. Such guidelines include security type, credit quality and maturity and are intended to limit market risk by restricting our investments. From time to time, our investments held with financial institutions may exceed Federal Deposit Insurance Corporation insurance limits. Interest rate fluctuations and changes in credit ratings impact the carrying value of our portfolio. Our outstanding borrowings under our Credit Agreement are subject to market risk, primarily interest rate risk. Interest rate fluctuations impact the interest expense incurred on borrowings under the Credit Agreement, as the interest rate is based on the London Interbank Offered Rate. During 2016, 2015 and 2014, we did not recognize revenue from any one customer that represented 10% or more of revenues. Cost of Revenue Cost of service revenue principally consists of the cost of customer service, system operating costs, credit card processing fees and customer misprints that do not qualify for reimbursement from the USPS. Cost of product revenue principally consists of the cost of products sold through our Supplies Stores and the related costs of shipping and handling. The cost of insurance revenue principally consists of parcel insurance offering costs through our third party insurance partners. Cost of customized postage revenue principally consists of the face value of postage, image review costs and printing and fulfillment costs. Deferred Revenue Our deferred revenue relates mainly to service revenue and PhotoStamps retail boxes. Deferred revenue related to our service revenue generally arises due to the timing of payment versus the provision of services for certain customers billed in advance. We previously sold PhotoStamps retail boxes to our customers through our website and selected third parties. Proceeds from the sale of our PhotoStamps retail boxes were initially recorded as a liability when received. We recorded the liability for outstanding PhotoStamps retail boxes in deferred revenue. We no longer sell PhotoStamps retail boxes. Fair Value of Financial Instruments Carrying amounts of certain of our financial instruments, including cash, cash equivalents, accounts receivable and accounts payable, approximate fair value due to their short maturities. The fair values of investments are determined using quoted market prices for those securities or similar financial instruments. The Company’s outstanding debt held by third-party financial institutions is carried at cost, adjusted for debt issuance costs. The Company’s debt is not publicly traded and the carrying amounts typically approximate fair value for debt that accrues interest at a variable rate for companies with similar financial characteristics as the Company, which are considered Level 2 inputs. The $63.2 million fair value of the contingent consideration liability related to our acquisition of ShipStation as of December 31, 2015 was calculated by multiplying the expected earn-out shares by our stock price. During 2015 we recorded approximately $47.4 million of charges relating to our contingent consideration liability of which $46.1 million was recorded in contingent consideration charges and $1.3 million was recorded in marketing and research and development in operating expenses. See Note 3 – “Acquisitions” General and Administrative General and administrative expense principally consists of compensation and related costs for executive and administrative personnel, fees for legal and other professional services, depreciation of equipment and software used for general corporate purposes and amortization of intangible assets. Goodwill Goodwill represents the excess of the fair value of consideration given over the fair value of the tangible assets, identifiable intangible assets and liabilities assumed in a business combination. We are required to test goodwill for impairment annually and whenever events or circumstances indicate the fair value of a reporting unit may be below its carrying value. Goodwill is reviewed for impairment annually on October 1. A reporting unit is the operating segment or a business that is one level below that operating segment. Reporting units are aggregated as a single reporting unit if they have similar economic characteristics. We aggregated our reporting units into a single reporting unit because we determined they have similar economic characteristics. There was no impairment to our goodwill related to our acquisitions. Goodwill is reviewed for impairment annually on October 1 st Impairment of Long-Lived Assets and Intangible Assets Long-lived assets including intangible assets with finite useful lives are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell. Intangible assets that have indefinite useful lives are not amortized but, instead, tested at least annually for impairment while intangible assets that have finite useful lives continue to be amortized over their respective useful lives. Income Taxes We account for income taxes in accordance with Financial Accounting Standards Board (“FASB”) ASC Topic No. 740, Income Taxes (“ASC 740”), which requires that deferred tax assets and liabilities be recognized using enacted tax rates for the effect of temporary differences between the book and tax basis of recorded assets and liabilities. ASC 740 also requires that deferred tax assets be reduced by a valuation allowance if it is more likely than not that some or all of the net deferred tax assets will not be realized. We record a valuation allowance to reduce our gross deferred tax assets to the amount that is more likely than not (a likelihood of more than 50 percent) to be realized. In order for us to realize our deferred tax assets, we must be able to generate sufficient taxable income. We evaluate the appropriateness of our deferred tax assets and related valuation allowance in accordance with ASC 740 based on all available positive and negative evidence. As of December 31, 2016 and 2015 we do not have any valuation allowance recorded to reduce our gross deferred tax assets as we believe we have met the more likely than not threshold we will realize our tax loss carry-forwards in the foreseeable future. Internet Advertising We recognize Internet advertising expense based on the specifics of the individual agreements. Under partner and affiliate agreements, third parties refer prospects to our web site, and we pay the third parties when the customer completes the customer registration process, or in some cases, upon the first successful billing of a customer. We record these expenses on a monthly basis as prospects are successfully converted to customers. Under Internet search advertising, we record expenses based on actual “click activity” on our displayed advertisements following targeted key word searches. Inventories Inventories consist of finished products sold through our supplies store and are accounted for using the lower of cost (first-in, first-out method) or market. Inventories reported as a component of other current assets in both 2016 and 2015 were $3.5 million. Net Income (loss) per Share Net income (loss) per share represents net income (loss) attributable to common stockholders divided by the weighted average number of common shares outstanding during a reported period. The diluted net income (loss) per share reflects the potential dilution that could occur if securities or other contracts to issue common stock, including stock options, (commonly and hereafter referred to as “common stock equivalents”), were exercised or converted into common stock. Diluted net income (loss) per share is calculated by dividing net income (loss) during a reported period by the sum of the weighted average number of common shares outstanding plus common stock equivalents for the period. The following table reconciles share amounts utilized to calculate basic and diluted net income (loss) per share (in thousands, except per share data): Year Ended December 31, 2016 2015 2014 Net income (loss) $ 75,229 $ (4,198 ) $ 36,882 Basic - weighted average common shares 17,245 16,436 16,011 Dilutive effect of common stock equivalents 1,006 — (1) 406 Diluted - weighted average common shares 18,251 16,436 16,417 Earnings (loss) per share: Basic $ 4.36 $ (0.26 ) $ 2.30 Diluted $ 4.12 $ (0.26 ) $ 2.25 (1) Common stock equivalents are excluded from the diluted net loss per share calculation as their effect is anti-dilutive. The shares related to the 2015 contingent consideration are not included because they are anti-dilutive. The calculation of dilutive shares excludes the effect of the following options that are considered anti-dilutive (in thousands): Year ended December 31, 2016 2015 2014 Anti-dilutive stock options 211 3,596 134 Property and Equipment We account for property and equipment at cost less accumulated depreciation and amortization. We compute depreciation using the straight-line method over the estimated useful life of the asset, generally three to five years for furniture, fixtures and equipment and ten to forty years for building and building improvements. We have a policy of capitalizing expenditures that materially increase assets’ useful lives and charging ordinary maintenance and repairs to operations as incurred. When property or equipment is disposed of, the cost and related accumulated depreciation and amortization are removed, and any gain or loss is included in operations. Research and Development Costs Research and development expense principally consists of compensation and related expenses for personnel involved in the development of our services, depreciation of equipment and software and expenditures for consulting services and third party software. Revenue Recognition We recognize revenue from product sales or services rendered, as well as commissions from advertising or sale of products by third party vendors to our customer base when the following four revenue recognition criteria are met: persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, the selling price is fixed or determinable, and collectability is reasonably assured. We earn service revenue in several different ways: (1) customers may pay us a monthly fee based on a subscription plan; (2) customers may qualify under our USPS partnership to have their service fees waived or refunded and then we are compensated directly by the USPS; (3) we may earn transaction related revenue based on customers purchasing postage or printing shipping labels; (4) we may earn compensation by offering customers a discounted postage rate that is provided to the customers by our integration partners; and (5) we may earn other types of revenue shares or other compensation from specific customers or integration partner, and is recognized in the period that services are provided. Customers purchase postage from the USPS through our mailing and shipping solutions. Postage purchase funds that are transferred directly from the customers to the USPS are not recognized as revenue for this postage, as it is purchased by our customers directly from the USPS. Customized postage revenue, which includes the face value of postage, from the sale of PhotoStamps and PictureItPostage sheets and rolls is made pursuant to a sales contract that provides for transfer of both title and risk of loss upon our delivery to the carrier and revenue is recognized at that time. On a limited basis, we allow third parties to offer products and promotions to our customer base. These arrangements generally provide payment in the form of a flat fee or revenue sharing arrangements where we receive payment upon customers accessing third party products and services. Total revenue from such advertising arrangements was not significant during 2016, 2015 and 2014. We provide our customers with the opportunity to purchase parcel insurance directly through our solutions. Insurance revenue represents the gross amount charged to the customer for purchasing insurance and the related cost represents the amount paid to our insurance providers. We recognize revenue on insurance purchases upon the ship date of the insured package. Sales and Marketing Sales and marketing expense principally consists of spending to acquire new customers and compensation and related expenses for personnel engaged in sales, marketing, and business development activities. Ongoing marketing programs include the following: traditional advertising, partnerships, customer referral programs, customer re-marketing efforts, telemarketing, direct sales, direct mail, and online advertising. Segment Information We operate in a single reportable segment, “Internet Mailing and Shipping Solutions.” Operating segments are defined as components of an enterprise for which discrete financial information is available that is evaluated regularly by the chief operating decision maker ("CODM") for purposes of allocating resources and evaluating financial performance. In 2015, we completed the reassessment of our segment reporting in light of our Endicia acquisition. Based on this reassessment, we identified two operating segments Segment Reporting The primary purpose of the CODM reviewing Endicia’s financial information was to inform resource allocation decisions relating to achieving potential acquisition related synergies including the following areas: (1) cost reductions for compensation and related expenses associated with duplicative personnel; (2) the planned level of sales and marketing spend; and (3) cost reductions from elimination of duplicative operational expenses and vendors. In 2016, we substantially realized the previously identified synergies and merged Endicia’s operations and employee groups into the existing consolidated structure which resulted in the CODM no longer needing to review Endicia’s performance and financial information separately. As a result, the Company's CODM now reviews the financial information presented on a consolidated basis for purposes of allocating resources and evaluating performance. Based on our evaluation in accordance with ASC 280, including consideration of the ShippingEasy acquisition, we concluded that we had one operating segment in 2016. In 2014, all of our operations, revenue and assets were within the United States. In 2015 and 2016, primarily as a result of our Endicia acquisition, we had international revenue and assets that were less than 1% of total revenue and assets with the remainder in the United States. During 2016, 2015 and 2014, we did not recognize revenue from any one customer that represented 10% or more of revenues. Short- Term Financing Obligations We utilize short-term financing, which is separate from our debt as described in Note – 7 “Debt,” Stock-Based Compensation We estimate the fair value of share-based payment awards on the date of grant using an option-pricing model and recognize stock-based compensation expense during each period based on the value of that portion of share-based payment awards that is ultimately expected to vest during the period, reduced for estimated forfeitures. We estimate forfeitures at the time of grant based on historical data and revise, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Compensation expense recognized for all employee stock options granted is recognized using the straight-line method over their respective vesting periods of up to five years. Starting in the third quarter of 2016, our stock-based compensation expense included performance based inducement equity awards relating to the ShippingEasy acquisition as described in Note 3 - Acquisitions The following table sets forth the stock-based compensation expense that we recognized for the periods indicated (in thousands): 2016 2015 2014 Stock-based compensation expense relating to: Employee and director stock options $ 32,891 $ 16,644 $ 4,473 Employee stock purchases 1,058 582 326 Total stock-based compensation expense $ 33,949 (2) $ 17,226 (1) $ 4,799 Stock-based compensation expense relating to: Cost of revenues $ 1,828 $ 995 $ 402 Sales and marketing 7,194 4,549 955 Research and development 6,633 3,149 998 General and administrative 18,294 8,533 2,444 Total stock-based compensation expense $ 33,949 (2) $ 17,226 (1) $ 4,799 (1) Included in this amount is $1.3 million of stock-based compensation expense relating to the change in the fair value of our contingent consideration liability in connection with our acquisition of ShipStation. See Note - 3 “Acquisitions.” (2) Included in this amount is $1.9 million of stock-based compensation expense relating to performance based equity awards granted in connection with our acquisition of ShippingEasy. See Note - 3 “Acquisitions.” We use the Black-Scholes-Merton option valuation model to estimate the fair value of share-based payment awards on the date of grant, which requires us to make a number of highly complex and subjective assumptions, including stock price volatility, expected term, risk-free interest rates and projected employee stock option exercise behaviors. In the case of options we grant, our assumption of expected volatility is based on the historical volatility of our stock price over the term equal to the expected life of the options. We base the risk-free interest rate on U.S. Treasury zero-coupon issues with a remaining term equal to the expected life of the options assumed at the date of grant. The estimated expected life represents the weighted-average period the stock options are expected to remain outstanding, determined based on an analysis of historical exercise behavior. The following are the weighted average assumptions used in the Black-Scholes valuation model for the periods indicated: 2016 2015 2014 Expected dividend yield — — — Risk-free interest rate 0.99 % 1.00 % 0.87 % Expected volatility 48 % 46 % 50 % Expected life (in years) 3.4 3.4 3.5 Expected forfeiture rate 6 % 6 % 6 % We elected to utilize the alternative transition method for calculating the tax effects of stock-based compensation. The alternative transition method includes computational guidance to establish the beginning balance of the additional paid-in capital pool (“APIC Pool”) related to the tax effects of employee stock-based compensation, and a simplified method to determine the subsequent impact on the APIC Pool for employee stock-based compensation awards that are vested and outstanding upon adoption of FASB ASC Topic No. 718 Compensation – Stock Compensation (“ASC 718”). A tax benefit will be recorded in additional paid-in capital when these deductions reduce our future income taxes payable. Trademarks, Patents and Intangible Assets Acquired trademarks, patents and other intangibles include both amortizable and non-amortizable assets and are included in intangible assets, net in the accompanying consolidated balance sheets. Intangible assets are carried at cost less accumulated amortization. Cost associated with internally developed intangible assets is typically expensed as incurred as research and development costs. Amortization of amortizable intangible assets is calculated on a straight-line basis, which is consistent with the expected future cash flows. Treasury During 2016 and 2014, we repurchased approximately 844,000 shares and 435,000 shares for $80.6 million and $12.9 million, respectively. We did not repurchase shares in 2015. Website Development Costs We develop and maintain our website. Costs associated with the operation of our website consist primarily of software and hardware purchased from third parties and administrative costs relating to the maintenance and development of the website. Costs related to the purchase of software and hardware are capitalized based on our property and equipment capitalization policy. These capitalized costs are amortized based on their estimated useful life. Administrative costs related to the maintenance and development of our website are expensed as incurred. Recent Accounting Pronouncements In May 2014, the FASB issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers ("ASU 2014-09") an updated standard on revenue recognition. This ASU will supersede the revenue recognition requirements in Accounting Standards Codification Topic 605, Revenue Recognition, and most industry-specific guidance. ASU 2014-09 provides enhancements to the quality and consistency of how revenue is reported while also improving comparability in the financial statements of companies reporting using US GAAP and International Financial Reporting Standards. The core principle of the new standard is for companies to recognize revenue to depict the transfer of goods or services to customers in amounts that reflect the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so the companies may be required to use more judgment and make more estimates than under current authoritative guidance. ASU 2014-09 will be effective for the Company in the first quarter of fiscal 2018 and may be applied on a full retrospective or modified retrospective approach. The Company has reviewed the ASU 2014-09 updated standard on revenue recognition. The Company is currently in the process of reviewing its material contracts to assess the impact of the new standard. While the Company has performed a review of the impact on certain contracts, it has not completed a review of all material contracts. As a result, the Company is currently still in the process of evaluating the adoption method and the impact the adoption of this standard will have on its consolidated financial statements. In February 2016, the FASB issued a new accounting standard for leases. The new standard generally requires the recognition of financing and operating lease liabilities and corresponding right-of-use assets on the balance sheet. For financing leases, a lessee recognizes amortization of the right-of-use asset as an operating expense over the lease term separately from interest on the lease liability. For operating leases, a lessee recognizes its total lease expense as an operating expense over the lease term. The amendments are effective for the Company in the first quarter of 2019 using a modified retrospective approach with early adoption permitted. The Company is currently evaluating the impact the adoption of this standard will have on its consolidated financial statements. In March 2016, the FASB simplified certain areas of accounting for stock-based compensation, including accounting for the income tax consequences of stock-based compensation, determining the classification of awards as either equity or liabilities, classifying certain items within the statement of cash flows and introducing an accounting policy election to account for forfeitures of non-vested awards as they occur. The simplified guidance is effective for the Company in the first quarter of 2017. Depending on the area simplified, the guidance is effective either prospectively, retrospectively or using a modified retrospective approach. Early adoption is permitted. The adoption of this standard will not have a material impact on our consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, a standard which simplifies the accounting for goodwill impairment. The guidance removes Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. Goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The revised guidance will be applied prospectively, and is effective for the Company in the first quarter of 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company is evaluating the effect this new standard will have on its financial statements.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2016
Acquisitions [Abstract]
Acquisitions	3. Acquisitions We have accounted for all of our acquisitions under the acquisition method of accounting in accordance with the provisions of FASB ASC Topic No. 805 Business Combinations ShippingEasy Acquisition On July 1, 2016, we completed our acquisition of ShippingEasy Group, Inc. (“ShippingEasy”) when our wholly owned subsidiary was merged with and into ShippingEasy, resulting in our 100% ownership of ShippingEasy. The merger agreement provided for us to pay $55.0 million in aggregate merger consideration to the former owners of ShippingEasy, payable in cash. The purchase price was subject to adjustments for changes in ShippingEasy’s net working capital. The net purchase price including adjustments for net working capital totaled approximately $55.4 million and was funded from current cash and investment balances. In connection with the acquisition, we issued performance based inducement equity awards to each of the General Manager and Chief Technology Officer of ShippingEasy. These inducement awards cover an aggregate of up to 43,567 common shares each if earnings targets for ShippingEasy are achieved over a two and one-half year period beginning July 1, 2016. The two and one-half year period is divided into three phases consisting of the six months ended December 31, 2016 and each of the twelve months ended December 31, 2017 and 2018. The awards are subject to proration if at least 75% of the applicable target is achieved and are subject to forfeiture or acceleration based on changes in employment circumstances over the performance period. The stock-based compensation expense associated with the performance based inducement equity award will be recognized ratably over each phase based on the estimated probable achievement of each financial target. The awards are a material inducement to the General Manager and Chief Technology Officer entering into employment agreements with Stamps.com in connection with the acquisition of ShippingEasy. We determined the achievement of 100% of the earnings target for the six months ended December 31, 2016 was met, therefore, we recognized approximately $1.9 million of stock-based compensation expense, representing 21,783 shares, for these inducement equity awards during the six months ended December 31, 2016. The $1.9 million stock-based compensation expense recognized represents 100% of the total performance based inducement equity award for the first phase. The equity award for the first phase will be issued in the first quarter of 2017. We also issued inducement stock option grants for an aggregate of approximately 62,000 shares of Stamps.com common stock to 48 new employees in connection with our acquisition of ShippingEasy. Each option vests 25% on the one year anniversary of the July 1, 2016 grant date with the remaining 75% vesting in approximately equal monthly increments over the immediately succeeding thirty-six months provided that the option holder is still employed by the Company on the vesting dates. The stock options have a ten year term and an exercise price equal to the closing price of Stamps.com common stock on the grant date of July 1, 2016. The stock options were granted as inducements material to the new employees entering into employment with Stamps.com in connection with the acquisition of ShippingEasy. The related stock-based compensation expense we recognized in 2016 was not material. The total net purchase price for the ShippingEasy acquisition was allocated to the assets acquired and the liabilities assumed based on their fair values. We have made significant estimates and assumptions in determining the allocation of the purchase price. The allocation of purchase consideration was subject to change based on finalizing the deferred tax liability and the valuation of the intangible assets as of the date of acquisition. During the fourth quarter of 2016, as a result of the finalization of the purchase price allocation, $173,000 was allocated to increase the deferred tax liability and goodwill balances. There were no changes to the valuation of intangible assets. The following table is the final allocation of the purchase price (in thousands, except years): Fair Value Fair Value Useful Life (In Years) Weighted Average Estimated Useful Life (In Years) Trade accounts receivable $ 1,194 Other assets 76 Property and equipment 40 Goodwill 40,953 Identifiable intangible assets: Trade name $ 1,304 8 Developed technology 6,948 5 Customer relationships 6,316 5 Non-compete agreements 1,111 3 to 5 Total identifiable intangible assets 15,679 5 Accrued expenses and other liabilities (707 ) Deferred revenue (185 ) Deferred tax liability (1,603 ) Total purchase price 55,447 Less: settlement of preexisting relationship (accounts receivable) 1,194 Purchase price, net of settlement $ 54, 253 Goodwill represents the excess of the fair value of consideration given over the fair value of the tangible assets, identifiable intangible assets and liabilities assumed in a business combination and the potential acquisition related synergies. Such synergies include leveraging Stamps.com’s resources, personnel, expertise and capital to grow ShippingEasy’s revenue faster than it otherwise would have as a standalone Company. The identified intangible assets consist of trade names, developed technology, non-compete agreements and customer relationships. The estimated fair values of the trademark and developed technology were determined using the “relief from royalty” method. The estimated fair value of the non-compete agreements was determined using the “with and without” method. The estimated fair value of customer relationships was determined using the “excess earnings” method. The rate utilized to discount net cash flows to their present values was approximately 23% and was determined after consideration of the overall enterprise rate of return and the relative risk and importance of the assets to the generation of future cash flows. Trademark, developed technology, non-compete and customer relationships are each amortized on a straight-line basis over their estimated useful lives. The amortization of acquired intangibles will be approximately $761,000 per quarter for the remaining estimated useful lives. The intangible assets and goodwill recorded in this acquisition are not deductible for tax purposes. Endicia Acquisition On March 22, 2015, we entered into a Stock Purchase Agreement (the “Stock Purchase Agreement”) with Endicia, and Newell Rubbermaid Inc., a Delaware corporation (“Newell”). The Stock Purchase Agreement provided for our purchase of all of the issued and outstanding shares of common stock of Endicia from a wholly owned indirect subsidiary of Newell for an aggregate purchase price of $215 million in cash (the “Transaction”). The purchase price was subject to adjustment for changes in Endicia’s net working capital as of the date of the closing of the Transaction and certain transaction expenses and closing cash adjustments. After receiving regulatory clearance, we closed the Transaction on November 18, 2015. As part of the funding of our acquisition of Endicia, we entered into a credit agreement with a group of banks on November 18, 2015, which provided for a term loan of $82.5 million and a revolving credit facility with a maximum borrowing of $82.5 million (collectively, the “Credit Agreement”) to fund our acquisition of Endicia. The Credit Agreement is secured by substantially all of our assets. We funded our acquisition with cash of $56.5 million and debt from our Credit Agreement of $164.5 million, totaling $221.0 million. The $221.0 million consisted of the following: 1) purchase price of $214.2 million; 2) $1.5 million of debt issuance costs; and 3) the transfer of Endicia’s ending cash balance on November 17, 2015 of $5.3 million. Total debt issuance costs of $1.8 million, which included $300,000 of costs incurred prior to closing, were recorded as debt discount and are being accreted as interest expense over the life of the Credit Agreement. Our Credit Agreement matures on November 18, 2020. As of December 31, 2016 our outstanding debt under the Credit Agreement, gross of debt issuance costs, was approximately $76.8 million under the term loan and approximately $72.0 million under the revolving credit facility. Because we have a letter of credit of approximately $510,000 relating to a facility lease, we have approximately $10.0 million of available and unused borrowings under the revolving credit facility as of December 31, 2016. See Note 7 – “Debt.” During the first quarter of 2016, we adjusted the purchase price allocation of Endicia which resulted in goodwill increasing by approximately $945,000 due to certain acquisition date balance sheet adjustments and the settlement of net working capital with Newell. The total estimated purchase price of the acquired company was allocated to the assets acquired and the liabilities assumed based on their fair values. We have made significant estimates and assumptions in determining the allocation of the purchase price. The following table sets forth the final allocation of the purchase price (in thousands, except years): Fair Value Fair Value Useful Life (In Years) Weighted Average Estimated Useful Life (In Years) Trade accounts receivable $ 10,247 Other assets 771 Property and equipment 2,798 Goodwill 131,860 Identifiable intangible assets: Trade name $ 10,900 Indefinite Developed technology 26,100 9 Customer relationships 43,200 6 Total identifiable intangible assets 80,200 7 Accrued expenses and other liabilities (10,212 ) Deferred revenue (926 ) Total purchase price $ 214,738 Goodwill represents the excess of the fair value of consideration given over the fair value of the tangible assets, identifiable intangible assets and liabilities assumed in a business combination and the potential synergy of combining the operations of Stamps.com and Endicia. Such synergies include estimated cost reductions and enhanced sales and customer support which are expected to drive increased volume. The entire amount of goodwill recorded in this acquisition is being deducted for tax purposes ratably over a 15 year period. The identified intangible assets consist of trade name, developed technology and customer relationships. The estimated fair values of the trade name and developed technology were determined using the “relief from royalty” method. The estimated fair value of customer relationships was determined using the “excess earnings” method. The rate utilized to discount net cash flows to their present values was approximately 20% and was determined after consideration of the overall enterprise rate of return and the relative risk and importance of the assets to the generation of future cash flows. Developed technology and customer relationships is being amortized on a straight-line basis over their estimated useful lives. The amortization of acquired intangibles is approximately $2.5 million per quarter for the remaining estimated useful lives. ShipWorks Acquisition On August 29, 2014, we acquired 100% of the outstanding equity of Interapptive Inc., which operates ShipWorks, in a cash transaction. The total purchase price for ShipWorks was approximately $22.1 million and was comprised of the following (in thousands): Fair Value Cash consideration $ 21,952 Deferred consideration 181 Total purchase price $ 22,133 The total purchase price of the acquired company was allocated to the assets acquired and the liabilities assumed based on their fair values. We have made significant estimates and assumptions in determining the allocation of the purchase price. During the fourth quarter of 2014, we adjusted the purchase price of ShipWorks by approximately $69,000. The following table sets forth the final allocation of the purchase price (in thousands, except years): Fair Value Fair Value Useful Life (In Years) Weighted Average Estimated Useful Life (In Years) Cash and cash equivalents $ 803 Trade accounts receivable 353 Other assets 21 Property and equipment 1,091 Goodwill 16,349 Identifiable intangible assets: Trademark $ 200 6 Developed technology 1,700 7 Non-compete agreement 700 4 Customer relationship 2,300 6 Total identifiable intangible assets 4,900 6 Accrued expenses and other liabilities (1,119 ) Deferred revenue (265 ) Total purchase price $ 22,133 Goodwill represents the excess of the fair value of consideration given over the fair value of the tangible assets, identifiable intangible assets and liabilities assumed in a business combination and the potential synergy of combining the operations of Stamps.com and ShipWorks. The entire amount of goodwill recorded in this acquisition is being deducted for tax purposes ratably over a 15 year period. The identified intangible assets consist of trademarks, developed technology, non-compete agreements and customer relationships. The estimated fair values of the trademark and developed technology were determined using the “relief from royalty” method. The estimated fair value of the non-compete was determined using the “with and without” method. The estimated fair value of customer relationship was determined using the “excess earnings” method. The rate utilized to discount net cash flows to their present values was approximately 13% and was determined after consideration of the overall enterprise rate of return and the relative risk and importance of the assets to the generation of future cash flows. Trademark, developed technology, non-compete and customer relationship is amortized on a straight-line basis over their estimated useful lives. The amortization of acquired intangibles is approximately $200,000 per quarter for the remaining estimated useful lives. ShipStation Acquisition and Contingent Consideration On June 10, 2014, we acquired 100% of the outstanding equity of Auctane LLC, which operates ShipStation, in a cash and contingent stock transaction. The total purchase price for ShipStation was approximately $66.2 million and was comprised of the following (in thousands, except shares): Fair Value Cash consideration $ 50,000 Fair value of performance linked earn-out of up to 768,900 shares of Stamps.com common stock (contingent consideration) 16,242 Total purchase price $ 66,242 The performance linked earn-out payment of Stamps.com shares (or contingent consideration) to former equity members of Auctane LLC was based on the achievement of certain financial measures within a time period subsequent to the acquisition. There were two periods in which the earn-out payment was calculated. The first earn-out period was based on the achievement of certain financial measures during the six months ended December 31, 2014. The second earn-out period was based on the achievement of certain financial measures during the twelve months ended December 31, 2015. The range of Stamps.com shares available for the performance linked earn-out for both periods was between 576,675 to 768,900 shares, provided that a minimum threshold for the financial measures was achieved. The first earn-out payment totaled 192,225 shares and was made in the first quarter of 2015. The second earn-out payment totaled 576,675 shares and was made in the first quarter of 2016. The fair value of the contingent consideration was determined at the acquisition date based on a probability weighted method, which incorporated management’s forecasts of financial measures and the likelihood of the financial measure targets being achieved using a series of options that replicate the pay-off structure of the earn-out, and the value of each of these options was determined using the Black-Scholes-Merton option pricing framework. The total purchase price of the acquired company was allocated to the assets acquired and the liabilities assumed based on their fair values. We have made significant estimates and assumptions in determining the allocation of the purchase price. The following table is the allocation of the purchase price (in thousands, except years): Fair Value Fair Value Useful Life Weighted Average Estimated Useful Life (In Years) Cash and cash equivalents $ 1,117 Trade accounts receivable 254 Other assets 39 Property and equipment 187 Goodwill 50,544 Identifiable intangible assets: Trademark $ 500 4 Developed technology 5,300 8 Non-compete agreement 400 4 Customer relationship 9,000 8 Total identifiable intangible assets 15,200 8 Accrued expenses and other liabilities (835 ) Deferred revenue (264 ) Total purchase price $ 66,242 Goodwill represents the excess of the fair value of consideration given over the fair value of the tangible assets, identifiable intangible assets and liabilities assumed in a business combination and the potential synergy of combining the operations of Stamps.com and ShipStation. The entire amount of goodwill recorded in this acquisition is being deducted for tax purposes ratably over a 15 year period. The identified intangible assets consist of trademarks, developed technology, non-compete agreements and customer relationships. The estimated fair values of the trademark and developed technology were determined using the “relief from royalty” method. The estimated fair value of the non-compete was determined using the “with and without” method. The estimated fair value of customer relationship was determined using the “excess earnings” method. The rate utilized to discount net cash flows to their present values was approximately 15% and was determined after consideration of the overall enterprise rate of return and the relative risk and importance of the assets to the generation of future cash flows. Trademark, developed technology, non-compete and customer relationship is amortized on a straight-line basis over their estimated useful lives. The amortization of acquired intangibles is approximately $500,000 per quarter for the remaining estimated useful lives. Under ASC 805, Business Combinations We incurred approximately $1.1 million, $4.4 million and $1.1 million in acquisition and integration related corporate development expenses during the years ended December 31, 2016, 2015 and 2014, respectively. These costs are included in general and administrative expense in our Consolidated Statements of Operations. Pro-Forma Financial Information (unaudited) The pro-forma information presented is for illustrative purposes only and is not necessarily indicative of the results of operations that would have been realized if the acquisition had been completed on the date indicated, nor is it indicative of future operating results. The pro-forma financial information does not include any adjustments for anticipated operating efficiencies or cost savings. The following table presents the pro-forma financial information (in thousands, except per share amounts) and assumes the acquisition of ShippingEasy occurred on January 1, 2015: Year Ended December 31, 2016 2015 Revenues $ 370,560 $ 219,426 Income (loss) from operations 121,537 (9,138 ) Net income (loss) 75,810 (6,608 ) Basic earnings (loss) per share $ 4.40 $ (0.40 ) Diluted earnings (loss) per share $ 4.15 $ (0.40 ) (1) (1) Common stock equivalents are excluded from the diluted net loss per share calculation as their effect is anti-dilutive. The following table presents the pro-forma financial information (in thousands, except per share amounts) and assumes the acquisition of Endicia occurred on January 1, 2014: Year Ended December 31, 2015 2014 Revenue $ 273,055 $ 204,628 (Loss) income from operations (7,657 ) 20,820 Net (loss) income (9,273 ) 32,536 (1) Basic (loss) earnings per share $ (0.58 ) $ 2.03 Diluted (loss) earnings per share $ (0.58 ) (2) $ 1.98 (1) Pro-forma net income of $32.5 million in 2014 includes valuation allowance releases of $13.6 million. (2) Common stock equivalents are excluded from the diluted net loss per share calculation as their effect is anti-dilutive. The following table presents the pro-forma financial information (in thousands, except per share amounts) and assumes the acquisition of ShipStation and ShipWorks occurred on January 1, 2013. Contingent consideration charge of approximately $8.8 million recognized in 2014 is excluded from the pro-forma information below: Year Ended December 31, 2014 2013 Revenue $ 154,459 $ 137,626 Income from operations 32,873 33,208 Net income 32,342 56,691 (1) Basic earnings per share $ 2.02 $ 3.61 Diluted earnings per share $ 1.97 $ 3.48 (1) Pro-forma net income of $56.7 million in 2013 includes valuation allowance releases of $13.6 million and $9.7 million recognized in 2014 and 2013, respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets [Abstract]
Goodwill and Intangible Assets	4. Goodwill and Intangible Assets Goodwill represents the excess of the fair value of consideration given over the fair value of the tangible assets, identifiable intangible assets and liabilities assumed in business combinations. The following tables summarize goodwill as of December 31, 2015 and 2016 (in thousands): 2015 Goodwill balance at December 31, 2014 $ 66,893 Acquisitions (see Note 3 – “Acquisitions” 130,914 Goodwill balance at December 31, 2015 $ 197,807 2016 Goodwill balance at December 31, 2015 $ 197,807 Purchase price adjustment (see Note 3 – “Acquisitions” 945 Acquisition of ShippingEasy (see Note 3 – “Acquisitions” 40,953 Goodwill balance at December 31, 2016 $ 239,705 We have amortizable and non-amortizable intangible assets consisting of patents, trademarks, trade names, developed technology, non-compete agreements,customer relationships and other totaling approximately $125.4 million and $109.7 million in gross carrying amount as of December 31, 2016 and 2015, respectively. Non-amortizable assets of $11.4 million consist primarily of trade name relating to the Endicia acquisition. The following table summarizes our amortizable intangible assets as of December 31, 2016 (in thousands): Gross Carrying Amount Accumulated Amortization Net Carrying Amount Patents and Others $ 8,889 $ 8,774 $ 115 Customer Relationships 60,816 12,199 48,617 Technology 40,048 6,100 33,948 Non-Compete 2,211 777 1,434 Trademark 2,004 479 1,525 Total amortizable intangible assets at December 31, 2016 $ 113,968 $ 28,329 $ 85,639 The following table summarizes our amortizable intangible assets as of December 31, 2015 (in thousands): Gross Carrying Amount Accumulated Amortization Net Carrying Amount Patents and Others $ 8,889 $ 8,729 $ 160 Customer Relationships 54,500 2,773 51,727 Technology 33,100 1,598 31,502 Non-Compete 1,100 389 711 Trademark 700 239 461 Total amortizable intangible assets at December 31, 2015 $ 98,289 $ 13,728 $ 84,561 We recorded amortization of intangible assets totaling approximately $14.6 million, $3.8 million and $1.6 million for the years ended December 31, 2016, 2015 and 2014, respectively, which is included in general and administrative expense in our accompanying consolidated statements of operations. As of December 31, 2016, the remaining weighted average amortization period for our amortizable intangible assets is approximately 6 years. Our estimated amortization expense for the next five years and thereafter is as follows (in thousands): Year Ending December 31, Estimated Amortization Expense 2017 $ 16,038 2018 15,854 2019 15,608 2020 15,440 2021 13,040 Thereafter 9,659 Total $ 85,639

Cash, Cash Equivalents and Inve

Cash, Cash Equivalents and Investments	12 Months Ended
	Dec. 31, 2016
Cash, Cash Equivalents and Investments [Abstract]
Cash, Cash Equivalents and Investments	5. Cash, Cash Equivalents and Investments Our cash equivalents and investments consist of money market, asset-backed securities and public corporate debt securities at December 31, 2016 and 2015. We consider all highly liquid investments with an original or remaining maturity of three months or less at the date of purchase to be cash equivalents. All of our investments are classified as available for sale and are recorded at market value using the specific identification method. Realized gains and losses are reflected in other income, net using the specific identification method. There was no material unrealized or realized gain or loss with respect to our investments during 2016, 2015 and 2014. Unrealized gains and losses are included as a separate component of stockholders' equity. We do not intend to sell investments with an amortized cost basis exceeding fair value and it is not likely that we will be required to sell the investments before recovery of their amortized cost bases. On at least a quarterly basis, we evaluate our available for sale securities and record an “other-than-temporary impairment” (“OTTI”) if we believe their fair value is less than historical cost and it is probable that we will not collect all contractual cash flows. We did not record any OTTI during 2016, 2015 and 2014 after evaluating a number of factors including, but not limited to: (1) how much fair value has declined below amortized cost; (2) the financial condition of the issuers; (3) significant rating agency changes on the issuers; and (4) our intent and ability to hold the security for a period of time sufficient to allow for any anticipated recovery in fair value The following tables summarize our cash, cash equivalents, and investments as of December 31, 2016 and 2015 (in thousands): December 31, 2016 Cost or Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and cash equivalents: Cash $ 101,987 — — $ 101,987 Money market 4,945 — — 4,945 Total cash and cash equivalents 106,932 — — 106,932 Short-term investments: Corporate bonds and asset backed securities 1,500 13 (2 ) 1,511 Total short-term investments 1,500 13 (2 ) 1,511 Long-term investments: Corporate bonds and asset backed securities — — — — Total long-term investments — — — — Cash, cash equivalents and investments $ 108,432 13 (2 ) $ 108,443 December 31, 2015 Cost or Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and cash equivalents: Cash $ 63,593 — — $ 63,593 Money market 1,533 — — 1,533 Total cash and cash equivalents 65,126 — — 65,126 Short-term investments: Corporate bonds and asset backed securities 8,549 7 (3 ) 8,553 Total short-term investments 8,549 7 (3 ) 8,553 Long-term investments: Corporate bonds and asset backed securities 1,515 17 (3 ) 1,529 Total long-term investments 1,515 17 (3 ) 1,529 Cash, cash equivalents and investments $ 75,190 24 (6 ) $ 75,208 The following table summarizes contractual maturities of our marketable fixed-income securities as of December 31, 2016 (in thousands): Amortized Cost Estimated Fair Value Due within one year $ 1,500 $ 1,511 Due after one year — — Total $ 1,500 $ 1,511

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
Fair Value Measurements [Abstract]
Fair Value Measurements	6. Fair Value Measurements Financial assets measured at fair value on a recurring basis are classified in one of the three following categories, which are described below: Level 1 - Valuations based on unadjusted quoted prices for identical assets in an active market Level 2 - Valuations based on quoted prices in markets where trading occurs infrequently or whose values are based on quoted prices of instruments with similar attributes in active markets Level 3 - Valuations based on inputs that are unobservable and involve management judgment and our own assumptions about market participants and pricing The following tables summarize our financial assets measured at fair value on a recurring basis as of December 31, 2016 and 2015 (in thousands): Fair Value Measurement at Reporting Date Using Description December 31, 2016 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 106,932 $ 106,932 $ — $ — Available-for-sale debt securities 1,511 — 1,511 — Total $ 108,443 $ 106,932 $ 1,511 $ — Fair Value Measurement at Reporting Date Using Description December 31, 2015 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 65,126 $ 65,126 $ — $ — Available-for-sale debt securities 10,082 — 10,082 — Total $ 75,208 $ 65,126 $ 10,082 $ — The fair value of our available-for-sale debt securities included in the Level 2 category is based on the market values obtained from an independent pricing service that were evaluated using pricing models that vary by asset class and may incorporate available trade, bid and other market information and price quotes from well-established independent pricing vendors and broker-dealers. As of December 31, 2015 we had $63.2 million of contingent consideration relating to our acquisition of ShipStation that was required to be measured at fair value using quoted prices in active markets (level 1) because the contingencies had been resolved as of that date. The following table summarizes our contingent consideration measured at fair value on a recurring basis (in thousands): Fair Value Measurement at Reporting Date Using Description December 31, 2015 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Contingent consideration – current $ 63,209 $ 63,209 $ — $ — The following table represents a reconciliation of contingent consideration obligation measured on a recurring basis using significant unobservable inputs (level 3) as of December 31, 2014 and then transferred to quoted prices in active markets (level 1) as of December 31, 2015 (in thousands): 2015 Beginning of year balance $ 25,015 Contingent consideration distribution (9,225 ) Contingent consideration charges (1) 46,088 Contingent consideration compensation expense (1) 1,331 End of year balance $ 63,209 The contingent consideration of $63.2 million was distributed in the first quarter of 2016. As of December 31, 2016, we had no contingent consideration. (1) This amount represents fair value adjustment during the year to contingent consideration recorded associated with the acquisition of ShipStation. The $46.1 million contingent consideration charge is recorded as a separate line item in our consolidated statement of income. The $1.3 million contingent consideration charge relating to certain employees is recorded in general and administrative expense in operating expense. See Note 3 – “Acquisitions” for further description. At December 31, 2015, the contingent consideration obligation was transferred from level 3 to level 1.

Debt

Debt	12 Months Ended
	Dec. 31, 2016
Debt [Abstract]
Debt	7. Debt On November 18, 2015, we entered into a Credit Agreement with a group of banks, which provides for a term loan of $82.5 million and a revolving credit facility with a maximum borrowing of $82.5 million. Our Credit Agreement matures on November 18, 2020. In connection with entering into the Credit Agreement, we incurred approximately $1.8 million in debt issuance costs which were recorded as debt discount and are being accreted as interest expense over the life of the Credit Agreement. Amortization expense associated with the debt issuance costs was approximately $373,000 and $31,000 for the years ended December 31, 2016 and 2015, respectively. As of December 31, 2016 our outstanding debt under the Credit Agreement, gross of debt issuance costs, was approximately $76.8 million under our term loan and approximately $72.0 million under our revolving credit facility. Because we have a letter of credit of approximately $510,000 relating to a facility lease, we have approximately $10.0 million of available and unused borrowings under the revolving credit facility as of December 31, 2016. Borrowings under the term loan are payable in quarterly installments which began on December 31, 2015. We pay interest on our Credit Agreement equal to the London Interbank Offered Rate plus an applicable margin, between 1.25% to 2.00%, based upon certain financial measures. As of December 31, 2016, our applicable margin was 1.25% and the interest rate on our outstanding loan was approximately 2.13%. We are subject to certain customary quarterly financial covenants under our Credit Agreement such as a maximum total leverage ratio and a minimum fixed charge coverage ratio. As of December 31, 2016, we were in compliance with the covenants of the Credit Agreement. The Credit Agreement includes negative covenants, subject to exceptions, restricting or limiting our ability to among other things, incur additional indebtedness, grant liens, repurchase stock, pay dividends and engage in certain investment, acquisition and disposition transactions. The Credit Agreement imposes certain requirements in order for us to make dividend payments. As of December 31, 2016, such requirements were: (i) our Consolidated Total Leverage Ratio, as defined in the Credit Agreement, must be less than 2.75 to 1.00; (ii) our Fixed Charge Coverage Ratio, as defined in the Credit Agreement, must be greater than 1.25 to 1.00; and (iii) our Liquidity as defined in the Credit Agreement must be greater than $20 million. As of December 31, 2016, our Consolidated Total Leverage Ratio was 0.86 to 1.00, our Fixed Charge Coverage Ratio was 22.11 to 1.00 and our Liquidity was approximately $117 million. Based on our actual financial condition and results of operations, we do not believe that the provisions of the Credit Agreement currently represent a restriction to our ability to pay dividends in permissible amounts. The contractual maturities of our debt obligations due subsequent to December 31, 2016 are as follows (in thousands): Amount 2017 $ 6,703 2018 8,766 2019 10,828 2020 122,521 2021 — Total debt 148,818 Less debt issuance costs 1,465 Total debt, net of debt issuance costs $ 147,353

Accounts Payable and Accrued Ex

Accounts Payable and Accrued Expenses	12 Months Ended
	Dec. 31, 2016
Accounts Payable and Accrued Expenses [Abstract]
Accounts Payable and Accrued Expenses	8. Accounts Payable and Accrued Expenses The following table summarizes our accounts payable and accrued expenses as of December 31, 2016 and 2015 (in thousands): 2016 2015 Payroll and related accrual $ 15,168 $ 12,863 Cost of revenue, inventory and materials accrual 977 539 Construction and facility expense accrual 1,899 649 Professional fees accrual 3,802 1,973 Sales and marketing related accrual 6,001 5,145 Operating expenses related accrual 35,285 15,613 Short-term financing obligations 15,554 13,313 Other accruals 7,519 10,721 Accounts payable and accrued expenses $ 86,205 $ 60,816

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2016
Property and Equipment [Abstract]
Property and Equipment	9. Property and Equipment Property and equipment is summarized as follows (in thousands): 2016 2015 Land $ 7,156 $ 7,156 Building 4,886 4,886 Building improvements 17,705 14,048 Leasehold improvements 2,003 1,055 Furniture and equipment 2,509 2,016 Computers and software 22,740 18,920 56,999 48,081 Less accumulated depreciation and amortization (20,170 ) (16,374 ) Property and equipment, net $ 36,829 $ 31,707 During 2016, 2015 and 2014, depreciation expense was approximately $4.6 million, $3.9 million and $3.2 million, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Taxes [Abstract]
Income Taxes	10. Income Taxes In 2016, our net income tax expense of $41.7 million consisted of current income tax expense consisting of federal alternative minimum tax and various state taxes and deferred income tax expense consisting of temporary tax items including contingent consideration, stock compensation and differences in the book and tax lives of amortizable intangibles. Our effective income tax rate differs from the statutory income tax rate primarily as a result of permanent tax adjustments for nondeductible items, research and development tax credits, and changes of state tax rates. We evaluated the appropriateness of our deferred tax assets and related valuation allowance in accordance with ASC 740 based on all available positive and negative evidence. During 2016, we recorded current income tax expense for alternative minimum federal taxes and state taxes of $8.1 million and deferred income tax expense resulting from pre-tax book income which included temporary tax adjustments for net operating losses, contingent consideration obligation, stock-based compensation and amortization of definite-lived intangible assets as well as various state rate changes totaling approximately $33.6 million, totaling to a net income tax expense of $41.7 million. During 2015, we recorded current income tax expense for alternative minimum federal taxes and state taxes of $1.4 million and deferred income tax benefit resulting from pre-tax book losses which included temporary tax adjustments for contingent consideration obligation, stock-based compensation and amortization of definite-lived intangible assets as well as various federal and state rate changes totaling approximately $2.8 million, totaling to a net income tax benefit of $1.4 million. During 2014, we recorded current income tax expense for alternative minimum federal taxes and state taxes of $856,000 and deferred income tax benefit for the release of our valuation allowance totaling approximately $13.6 million, totaling to a net income tax benefit of $12.7 million. As of December 31, 2016, we have approximately $48.8 million of net deferred tax assets and we do not have any valuation allowance. In determining that a valuation allowance was not necessary, we considered the available positive and negative evidence, including our recent earnings trend, expected future income and the federal and state effective tax rates related to the future income. Under the guidance related to uncertain tax positions, we are required to determine whether it is more likely than not that a tax position will be sustained upon examination based on the technical merits of the position. A tax position that meets the more likely than not recognition threshold is measured to determine the amount of liability or benefit to recognize in the financial statements. In accordance with the guidance we have evaluated our research and development tax credits for uncertain tax positions. As of December 31, 2016 we have research and development tax credit carryforwards totaling $10.3 million, net of unrecognized tax benefit for Federal and California purposes. The following is a tabular reconciliation of the total amounts of unrecognized tax benefits for the years ended December 31, 2016, 2015 and 2014 (in thousands): Unrecognized Tax Benefits Balance at December 31, 2013 $ (2,314 ) Addition for tax positions of prior years (2,349 ) Addition for tax position of the current year (560 ) Settlement — Balance at December 31, 2014 $ (5,223 ) Addition for tax positions of prior years (251 ) Addition for tax position of the current year (560 ) Settlement — Balance at December 31, 2015 $ (6,034 ) Additions for tax positions of prior years (810 ) Reduction for tax positions of prior years 2,596 Additions for tax position of the current year (2,156 ) Settlement 251 Balance at December 31, 2016 $ (6,153 ) Included in the balance of unrecognized tax benefits as of December 31, 2016, 2015, and 2014, are $6.2 million, $6 million, and $5.2 million, respectively, of tax benefits that, if recognized, would affect the effective tax rate. Our policy is to recognize interest and penalties related to unrecognized tax benefits as a component of income tax expense. There was no material interest or penalty expense during the years ended December 31, 2016, 2015 and 2014. We believe that it is reasonably possible that a decrease of up to $2.6 million in unrecognized tax benefits related to state exposures may occur within the coming year. We are subject to taxation in the U.S. and various state jurisdictions. We are subject to income tax examination by U.S. and state tax authorities for the calendar year ended December 31, 2013 and forward. However, to the extent allowed by law, the taxing authorities may have the right to examine prior periods where NOLs and credits were generated and carried forward, and make adjustments up to the amount of the NOLs and credits utilized in open tax years. Our effective income tax rate differs from the statutory income tax rate primarily as a result of permanent tax adjustments for nondeductible items, research and development tax credits, and changes of state tax rates. The tax effect of temporary differences that give rise to a significant portion of the deferred tax assets and liabilities at December 31, 2016 and 2015 are presented below (in thousands): 2016 2015 Deferred tax assets: Net operating loss carryforward $ 3,406 $ 22,024 Tax credit carryforwards 16,091 6,872 Definite lived intangibles 200 2,946 Contingent consideration 20,461 20,742 Stock compensation 12,162 4,800 Accruals 7,771 3,534 Deferred tax assets 60,091 60,918 Deferred tax liabilities: Fixed assets (726 ) (464 ) Indefinite lived intangibles (7,770 ) (1,922 ) Federal benefit of state tax deferred tax assets (2,813 ) (1,308 ) Deferred tax liabilities (11,309 ) (3,694 ) Net deferred tax assets $ 48,782 $ 57,224 We have NOL carry-forwards of approximately $15.7 million for federal income tax purposes at December 31, 2016 which can be carried forward to offset future taxable income. We do not have any material state NOL carryforwards. We have available tax credit carry-forwards of approximately $11.4 million and $4.7 million, net of unrecognized tax benefit for federal and state income tax purposes, respectively at December 31, 2016, which can be carried forward to offset future taxable liabilities. Our federal NOLs will begin to expire in 2020. The federal tax credits begin to expire in 2019. Under California law, California tax credits do not have an expiration date. We recognize excess tax benefits associated with the exercise of stock options directly to stockholders’ equity only when realized. We have made an accounting policy election to exclude from the measurement of the excess tax deduction any indirect effects of the tax deduction. Accordingly, deferred tax assets are not recognized for NOL carry-forwards resulting from excess tax benefits. As of December 31, 2016, deferred tax assets do not include approximately $6 million of these excess tax benefits from employee stock option exercises that are a component of our NOL carry-forwards. Accordingly, additional paid-in capital will increase up to an additional $6 million if and when such excess tax benefits are realized. Based on our election under ASC 718 to use the “with-and-without” approach when utilizing net operating losses consisting of other operating losses and excess tax benefits, the excess tax benefit will be deemed to be the last benefit utilized, and in accordance with ASC 718, benefits for share based payments are not recorded to APIC until such payments result in a reduction to income taxes payable. Our 2016 income tax provision utilized federal and state APIC tainted net operating loss in the current year resulting in a reduction to income taxes payable and a benefit to APIC in the amount of $26.8 million. The Federal Tax Reform Act of 1986 and similar state tax laws contain provisions that may limit the NOL carryforwards to be used in any given year upon the occurrence of certain events, including a significant change in ownership interests. Under IRC Section 382 rules, a change in ownership can occur whenever there is a shift in ownership by more than 50 percentage points by one or more “5% shareholders” within a three-year period. When a change of ownership is triggered, the NOLs may be impaired. In July 2016, we acquired ShippingEasy Group, Inc. (ShippingEasy) which had a federal tax attribute carryforward of approximately $12 million. As a consequence of the ownership change, our federal tax attribute carryforward was subject to limitation under IRC Section 382. We conducted an analysis to compute the limitations and utilization of ShippingEasy’s NOLs as allowed under Section 382 and expect to utilize all carryforwards before their expiration. The income tax expense (benefit) consists of (in thousands): 2016 2015 2014 Current: Federal $ 2,400 $ 806 $ 730 State 5,722 611 127 8,122 1,417 857 Deferred: Federal 11,023 (596 ) (14,286 ) State (3,403 ) (1,341 ) 652 Adjustment for change in tax rate (781 ) (1,471 ) 80 APIC charge on excess tax benefits 26,784 618 — 33,623 (2,790 ) (13,554 ) Income tax expense (benefit) $ 41,745 $ (1,373 ) $ (12,697 ) Differences between the benefit for income taxes and income taxes at the statutory federal income tax rate are as follows (in thousands): 2016 2015 2014 Income tax at statutory federal rate $ 40,941 $ (1,950 ) $ 8,223 State tax – net of federal benefit 4,127 (2 ) 290 Stock-based compensation 2,757 851 497 Nondeductible items 485 902 15 Research and development (1,963 ) — — Uncertain tax positions (2,048 ) 173 1,767 Change in tax rate (781 ) (1,471 ) 80 Change in valuation allowance — — (13,554 ) Other changes in valuation allowance, net — — (11,480 ) Other, net (1,773 ) 124 1,465 $ 41,745 $ (1,373 ) $ (12,697 ) In 2016, we revised our estimated annual effective tax rate to reflect a change in the state statutory rates as well as additional state filings effective January 1, 2016. As a result, we recorded a $0.8 million deferred tax benefit from the application of the change in tax rate to the net deferred tax assets. The Company completed a study in 2016 regarding the calculation of research and development credit carryforwards. As a result of the analysis, the Company recognized deferred tax assets for federal and state research and development credits of approximately $6 million.

Employee Stock Plans

Employee Stock Plans	12 Months Ended
	Dec. 31, 2016
Employee Stock Plans [Abstract]
Employee Stock Plans	11. Employee Stock Plans Stock Incentive Plans Our 1999 Stock Incentive Plan (the “1999 Plan”), which became effective in June 1999, was the successor to the 1998 Stock Plan (the “1998 Plan”). Upon approval of the 1999 Plan, all outstanding options under the 1998 Plan were transferred to the 1999 Plan, and no further option grants were made under the 1998 Plan. All outstanding options under the 1998 Plan continue to be governed by the terms and conditions of the existing option agreements for those grants, unless our compensation committee decides to extend one or more features of the 1999 Plan to those options. In June 2009, our 1999 Plan expired and no further options grants were made under the 1999 Plan. Our 2010 Equity Incentive Plan (the “2010 Plan”) was approved by our stockholders in June 2010. Under the 2010 Plan, we are authorized to issue 3,500,000 shares of common stock and stock units, although “full value” awards (such as restricted stock and restricted stock units) will be counted against the 2010 Plan’s overall limits as two shares (rather than one), while options and stock appreciation rights will be counted as one share. On September 9, 2014, our Board of Directors approved an amendment (the “2014 Amendment”) to our 2010 Plan, which was approved by our shareholders on June 17, 2015. Pursuant to the 2014 Amendment, the maximum aggregate number of shares of common stock and stock units available for the grant of awards under the 2010 Plan was increased by an additional 2,100,000 shares. On April 28, 2016, our Board of Directors adopted an amendment (the “2016 Amendment”), subject to shareholder approval, to increase the maximum aggregate number of shares of common stock and stock units available for grants by an additional 1,200,000 shares. The number of shares of common stock remaining available for future issuance under the equity compensation plans was 1,370,000 excluding the number of shares of common stock to be issued upon exercise of outstanding options, warrants and rights. The 2016 Amendment was approved by our shareholders on June 13, 2016. Except for the 2014 and 2016 Amendments to the Plan to increase the number of shares issuable, the Plan otherwise remains unchanged. On April 9, 2015, pursuant to the 2014 Amendment, our compensation committee approved additional performance-based stock option grants for certain of our employees. These additional option awards granted under the 2014 Amendment vest monthly in equal parts over a 36-month period that commenced on the closing of our acquisition of Endicia. The number of options issued was approximately 175,000. For these awards subject to performance conditions, the fair value per award was fixed at the grant date on June 17, 2015, the date the 2014 Amendment was approved by the shareholders. A summary of stock option activity is as follows (in thousands, except per share amounts): Options Outstanding Weighted Average Exercise Price per Share Number of Options Balance at December 31, 2013 996 $ 18.12 Granted 2,251 32.55 Forfeited (75 ) 35.96 Exercised (203 ) 16.34 Balance at December 31, 2014 2,969 $ 28.91 Granted 694 65.96 Forfeited (98 ) 37.43 Exercised (459 ) 23.73 Balance at December 31, 2015 3,106 $ 37.75 Granted 816 91.36 Forfeited (198 ) 72.72 Exercised (432 ) 30.04 Balance at December 31, 2016 3,292 $ 49.95 The weighted-average fair value of stock options granted for 2016, 2015 and 2014 using the Black-Scholes valuation method are as follows: 2016 2015 2014 Weighted-average fair value of stock options with an exercise price equal to the market price on the grant date $ 32.27 $ 23.19 $ 11.87 Weighted-average fair value of stock options with an exercise price greater than the market price on the grant date — — — Total $ 32.27 $ 23.19 $ 11.87 Weighted average exercise prices for stock options exercised in 2016 are as follows: 2016 Weighted-average exercise price of stock options with an exercise price equal to the market price on the grant date $ 30.04 Weighted-average exercise price of stock options with an exercise price greater than the market price on the grant date — Total weighted-average exercise price $ 30.04 The following tables summarize information concerning outstanding and exercisable options at December 31, 2016 (in thousands, except numbers of years and per share amounts): Options Outstanding Options Exercisable Range of Exercise Prices Number Outstanding Weighted Average Remaining Contractual Life (in Years) Weighted Average Exercise Price per Share Number Exercisable Weighted Average Exercise Price per Share $0.00 - $9.99 18 2.3 $ 9.12 18 $ 9.12 $10.00 - $19.99 197 4.0 12.62 197 12.62 $20.00 - $29.99 89 6.0 26.17 79 25.83 $30.00 - $39.99 1,649 7.7 32.57 1,132 32.59 $40.00 - $49.99 72 7.6 45.23 43 45.06 $50.00 - $59.99 122 8.2 58.25 68 58.25 $60.00 - $69.99 216 8.3 66.00 77 66.12 $70.00 - $79.99 256 8.8 73.73 72 72.25 $80.00 - $89.99 266 9.2 87.24 — — $90.00 - $99.99 361 9.4 94.51 22 91.86 $100.00 - $109.99 42 9.6 104.11 3 101.32 $120.00 - $129.99 5 9.2 122.25 — — $0.00 - $129.99 3,293 7.9 $ 49.95 1,711 $ 35.14 The following table summarizes stock option activity for 2016: Number of Stock Options (in thousands) Weighted Average Exercise Price Weighted Average Remaining Contractual Life (in years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2015 3,106 $ 37.75 Granted 816 91.36 Exercised (432 ) 30.04 Forfeited or expired (198 ) 72.72 Balance at December 31, 2016 3,292 $ 49.95 7.9 $ 213,066 Exercisable at December 31, 2016 1,711 $ 35.14 7.2 $ 136,056 The aggregate intrinsic value in the table above represents the total pretax intrinsic value, based on our closing stock price of $114.65 at December 30, 2016, the last trading day of 2016, which would have been received by award holders had all award holders exercised their awards that were in-the-money as of that date. The weighted average grant date fair value of options granted during 2016, 2015 and 2014 was $32.27, $23.19 and $11.87, respectively. The weighted average grant date fair value of options vested during 2016, 2015 and 2014 was $30.68, $12.46 and $8.44, respectively. The total intrinsic value of options exercised during 2016, 2015 and 2014 was approximately $36.5 million, $39.4 million and $6.4 million, respectively. The following table summarizes the status of our non-vested stock options as of December 31, 2016: Non-vested Number of Stock Options (in thousands) Weighted Average Grant Date Fair Value per Option Non-vested at December 31, 2015 1,900 $ 29.62 Granted 816 32.37 Vested (1,092 ) 30.68 Forfeited / Cancelled (42 ) 21.65 Non-vested at December 31, 2016 1,582 $ 30.35 As of December 31, 2016, there was $44.5 million of total unrecognized compensation cost related to non-vested share-based compensation arrangements, which is expected to be recognized over a weighted-average period of approximately 2 years. Equity Inducement Plans In connection with the ShippingEasy acquisition, we issued performance based inducement equity awards to two executives of ShippingEasy covering an aggregate of up to approximately 87,000 shares of common stock if earnings targets for ShippingEasy are achieved over a two and one-half year period beginning July 1, 2016. The awards are subject to proration if at least 75% of the applicable target is achieved and are subject to forfeiture or acceleration based on changes in employment circumstances over the performance period. In addition, in connection with the ShippingEasy acquisition we made inducement stock option grants for an aggregate of 62,000 shares of Stamps.com common stock to 48 employees. Each option vests 25% on the one year anniversary of the grant date and the remaining 75% vesting in approximately equal monthly increments over the succeeding thirty-six months provided that the option holder is still employed by the Company on the vesting dates. The stock options have a ten year term and an exercise price equal to the closing price of Stamps.com common stock on the grant date of July 1, 2016. The two inducement plans were exempt from stockholder approval requirements as an employment inducement grant plan under applicable Nasdaq Listing Rule 5635(c)(4) as inducements material to the new employees entering into employment with Stamps.com. Employee Stock Purchase Plan In June 1999, our Board of Directors adopted an Employee Stock Purchase Plan (ESPP), which allows our eligible employees to purchase shares of common stock, at semi-annual intervals, with their accumulated payroll deductions. Eligible participants may contribute up to 15% of cash earnings through payroll deductions, and the accumulated deductions will be applied to the purchase of shares on each semi-annual purchase date. The purchase price per share is equal to 85% of the fair market value per share on the participant’s entry date into the offering period or, if lower, 85% of the fair market value per share on the semi-annual purchase date. Upon adoption of the ESPP, 150,000 shares of common stock were reserved for issuance. This reserve automatically increases on the first trading day in January each year, by an amount equal to 1% of the total number of outstanding shares of our common stock on the last trading day in December in the prior year. In no event will any annual increase exceed 260,786 shares. In July 2009, our Board of Directors amended our ESPP to extend it for a period of ten years beyond its original expiration date of July 31, 2009. Under this amendment, the total shares available for issuance may not increase. As of December 31, 2016 and 2015, we had approximately 1.6 million shares available for issuance under our ESPP. Total shares of common stock issued pursuant to the ESPP during 2016, 2015 and 2014 were approximately 35,000, 49,000, and 42,000, respectively. Savings Plan We have a savings plan for all eligible employees which qualifies under Section 401(k) of the Internal Revenue Code. Participating employees may contribute any percentage of their pretax salary, but not more than statutory dollar limits. We match participant contributions up to certain limitations. We expensed approximately $1.1 million, $650,000 and $402,000 in 2016, 2015 and 2014, respectively, related to this plan.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies Legal Proceedings We are subject to various routine legal proceedings and claims incidental to our business, and we do not believe that these proceedings and claims would reasonably be expected to have a material adverse effect on our financial position, results of operations or cash flows. Although management at present believes that the ultimate outcome of the various routine proceedings, individually and in the aggregate, will not materially harm our financial position, results of operations, cash flows, or overall trends, legal proceedings are subject to inherent uncertainties, and unfavorable rulings or other events could occur. An unfavorable outcome for an amount in excess of management’s present expectations may result in a material adverse impact on our business, results of operations, financial position, and overall trends. Commitments The Company leases facilities pursuant to noncancelable operating lease agreements expiring through 2021. Rent expense is recognized on a straight-line basis over the lease term. Lease incentives are amortized over the lease term on a straight-line basis. Leasehold improvements are capitalized and amortized over the shorter of the useful life of the asset or the remaining term of the lease. Rent expense was approximately $3.0 million, $874,000, and $215,000 for the years ended December 31, 2016, 2015 and 2014, respectively. The following table is a schedule of our significant contractual obligations and commercial commitments (other than debt commitments, which are summarized in Note 7- “Debt” Twelve Month Period Ending December 31, Operating Lease Obligations 2017 $ 4,048 2018 3,563 2019 1,369 2020 1,396 2021 1,052 Thereafter — Total $ 11,428

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Events We are not aware of any material subsequent events or transactions that have occurred that would require recognition in the financial statements or disclosure in the notes to the financial statements.

Quarterly Information (Unaudite

Quarterly Information (Unaudited)	12 Months Ended
	Dec. 31, 2016
Quarterly Information (Unaudited) [Abstract]
Quarterly Information (Unaudited)	14. Quarterly Information (Unaudited) Quarter Ended March June September (3) December (2) (in thousands except per share data) Fiscal Year 2016: Revenues $ 81,837 $ 84,013 $ 92,559 $ 105,896 Gross profit 67,215 70,293 75,832 87,993 Income from operations 22,219 24,967 31,591 41,443 Net income 13,238 14,291 18,672 29,028 Net income per share: Basic $ 0.76 $ 0.82 $ 1.08 $ 1.71 Diluted $ 0.71 $ 0.79 $ 1.03 $ 1.61 Weighted average shares outstanding: Basic 17,357 17,384 17,218 17,018 Diluted 18,664 18,192 18,120 18,026 Fiscal Year 2015: Revenues $ 44,052 $ 48,360 $ 51,669 $ 69,876 Gross profit 34,427 38,422 40,480 56,693 Income (loss) from operations (2,159 ) (15,152 ) 12,991 (1,000 ) Net (loss) income (970 ) (10,431 ) 7,274 (71 ) Net (loss) income per share: Basic $ (0.06 ) $ (0.64 ) $ 0.44 $ (0.00 ) Diluted $ (0.06 ) $ (0.64 ) $ 0.42 $ (0.00 ) Weighted average shares outstanding: Basic 16,156 16,402 16,538 16,642 Diluted 16,156 (1) 16,402 (1) 17,517 16,642 (1) Quarterly and year-to-date computations of per share amounts are made independently. Therefore, the sum of per share amounts for the quarters may not agree with per share amounts for the year shown elsewhere in our Annual Report on Form 10-K. (1) Common stock equivalents are excluded from the diluted earnings per share calculation as their effect is anti-dilutive. (2) The fourth quarter results of 2015 include the impact of the Company’s acquisition of Endicia. (3) The third and fourth quarter results of 2016 include the impact of the Company’s acquisition of ShippingEasy.

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Summary of Significant Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of Stamps.com Inc., Auctane LLC, Interapptive, Inc., PSI Systems Inc., ShippingEasy Group, Inc., and PhotoStamps Inc. In June 2014, we completed our acquisition of 100% of the outstanding equity of Auctane LLC, a Texas limited liability company that operates ShipStation (“Auctane LLC” or “ShipStation”) in a cash and contingent stock transaction. ShipStation, based in Austin, Texas, offers web-based multi-carrier shipping solutions primarily under the brands ShipStation and Auctane. In August 2014, we completed our acquisition of 100% of the outstanding equity of Interapptive, Inc., a Missouri corporation, that operates ShipWorks (“Interapptive, Inc.” or “ShipWorks”) in a cash transaction. ShipWorks, based in St. Louis, Missouri, offers software-based multi-carrier shipping solutions. In November 2015, we completed our acquisition of 100% of the outstanding shares of PSI Systems, Inc. (“Endicia”). Endicia, based in Mountain View, California, offers mailing and shipping solutions for use with the USPS. In July 2016, we completed our acquisition of 100% of the outstanding shares of ShippingEasy Group, Inc. (“ShippingEasy”). ShippingEasy, based in Austin, Texas, offers web-based multi-carrier shipping solutions. See Note 3 – “Acquisitions” Because 100% of the voting control of Auctane LLC, Interapptive, Inc., PSI Systems, Inc., and ShippingEasy Group, Inc. is held by us, we have consolidated the results of operations of ShipStation, ShipWorks, Endicia and ShippingEasy from the date we obtained control in the accompanying consolidated financial statements. Similarly, due to our 100% control of PhotoStamps, Inc., PhotoStamps Inc. is also consolidated in the accompanying consolidated financial statements from the date of its inception. All significant intercompany accounts and transactions have been eliminated.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles (“US GAAP”) requires us to make estimates and assumptions that affect the amounts reported in the financial statements and the accompanying notes. Actual results could differ from those estimates, and such differences may be material to the financial statements. Examples include estimates of loss contingencies, realizability of deferred income taxes, the estimates and assumptions used to calculate stock-based compensation, the estimates and assumptions used to calculate the allocation of the purchase price related to our acquisitions, including related contingent consideration, and estimates regarding the useful lives of our building, patents and other amortizable intangible assets, and goodwill.
Accounts Receivable	Accounts Receivable Our accounts receivable relate to mailing and shipping services, postage purchasing and invoicing, PhotoStamps sales, and branded insurance provided to customers prior to billing and other receivables. Accounts receivable are recorded at the invoiced amount, net of allowances for uncollectible accounts of approximately $1,188,000, $831,000 and $414,000 as of December 31, 2016, 2015 and 2014, respectively. We evaluate the collectability of our accounts receivable based on a combination of factors. If we become aware of a customer’s inability to meet its financial obligations, an allowance is recorded to reduce the net receivable to the amount reasonably believed to be collectible from the customer. For all other customers, we recognize allowances for doubtful accounts based on the length of time the receivables are past due, the current business environment and our historical experience. If the financial condition of our customers deteriorates, resulting in their inability to make payments, additional provisions are recorded in that period. Accounts receivable are written off against the allowance for uncollectible accounts when we determine amounts are no longer collectible. Increases in allowance for doubtful accounts totaled approximately $356,000, $417,000 and $131,000 for 2016, 2015 and 2014, respectively. There were no material write offs against the allowance for doubtful accounts during 2016, 2015 or 2014.
Advertising Costs	Advertising Costs We expense the costs of producing advertisements as incurred, and expense the costs of communicating and placing the advertising in the period in which the advertising space or airtime is used. For the years ended December 31, 2016, 2015 and 2014, advertising and tradeshow costs were $12.1 million, $10.8 million and $9.7 million, respectively.
Business Combinations	Business Combinations The acquisition method of accounting is used for business combinations. The results of operations of acquired businesses are included in our consolidated financial statements prospectively from the date of acquisition. The fair value of purchase consideration is allocated to the assets acquired and liabilities assumed from the acquired entity and is generally based on their fair value at the acquisition date. The excess of the fair value of purchase consideration over the fair value of the assets acquired and liabilities assumed is recorded as goodwill. Historically the primary items that have generated goodwill include anticipated synergies between the acquired business and the Company and the acquired assembled workforce, neither of which qualifies for recognition as an intangible asset. Acquisition-related expenses are recognized in our consolidated financial statements as incurred.
Contingencies and Litigation	Contingencies and Litigation We are subject to various routine litigation matters as a claimant and a defendant. We record any amounts recovered in these matters when received. We establish loss provisions for claims against us when the loss is both probable and can be reasonably estimated. If either or both of the criteria are not met, we assess whether there is at least a reasonable possibility that a loss, or additional losses, may have been incurred. If there is a reasonable possibility that a loss or additional loss may have been incurred for such proceedings, we disclose the estimate of the amount of loss or possible range of loss, or disclose that an estimate of loss cannot be made, as applicable.
Cash Equivalents and Investments	Cash Equivalents and Investments We consider all highly liquid investments with an original or remaining maturity of three months or less at the date of purchase to be cash equivalents. Our cash equivalents and investments consisted of money market funds, asset-backed securities and public corporate debt securities at December 31, 2016 and 2015. All investments are classified as available for sale and are recorded at market value using the specific identification method. Realized gains and losses are reflected in interest and other income, net while unrealized gains and losses are included as a separate component of stockholders' equity.
Concentration of Risk	Concentration of Risk Our cash, cash equivalents and investments are subject to market risk, primarily interest rate and credit risk. Our investments are managed by a limited number of outside professional managers within investment guidelines set by us. Such guidelines include security type, credit quality and maturity and are intended to limit market risk by restricting our investments. From time to time, our investments held with financial institutions may exceed Federal Deposit Insurance Corporation insurance limits. Interest rate fluctuations and changes in credit ratings impact the carrying value of our portfolio. Our outstanding borrowings under our Credit Agreement are subject to market risk, primarily interest rate risk. Interest rate fluctuations impact the interest expense incurred on borrowings under the Credit Agreement, as the interest rate is based on the London Interbank Offered Rate. During 2016, 2015 and 2014, we did not recognize revenue from any one customer that represented 10% or more of revenues.
Cost of Revenue	Cost of Revenue Cost of service revenue principally consists of the cost of customer service, system operating costs, credit card processing fees and customer misprints that do not qualify for reimbursement from the USPS. Cost of product revenue principally consists of the cost of products sold through our Supplies Stores and the related costs of shipping and handling. The cost of insurance revenue principally consists of parcel insurance offering costs through our third party insurance partners. Cost of customized postage revenue principally consists of the face value of postage, image review costs and printing and fulfillment costs.
Deferred Revenue	Deferred Revenue Our deferred revenue relates mainly to service revenue and PhotoStamps retail boxes. Deferred revenue related to our service revenue generally arises due to the timing of payment versus the provision of services for certain customers billed in advance. We previously sold PhotoStamps retail boxes to our customers through our website and selected third parties. Proceeds from the sale of our PhotoStamps retail boxes were initially recorded as a liability when received. We recorded the liability for outstanding PhotoStamps retail boxes in deferred revenue. We no longer sell PhotoStamps retail boxes.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Carrying amounts of certain of our financial instruments, including cash, cash equivalents, accounts receivable and accounts payable, approximate fair value due to their short maturities. The fair values of investments are determined using quoted market prices for those securities or similar financial instruments. The Company’s outstanding debt held by third-party financial institutions is carried at cost, adjusted for debt issuance costs. The Company’s debt is not publicly traded and the carrying amounts typically approximate fair value for debt that accrues interest at a variable rate for companies with similar financial characteristics as the Company, which are considered Level 2 inputs. The $63.2 million fair value of the contingent consideration liability related to our acquisition of ShipStation as of December 31, 2015 was calculated by multiplying the expected earn-out shares by our stock price. During 2015 we recorded approximately $47.4 million of charges relating to our contingent consideration liability of which $46.1 million was recorded in contingent consideration charges and $1.3 million was recorded in marketing and research and development in operating expenses. See Note 3 – “Acquisitions”
General and Administrative	General and Administrative General and administrative expense principally consists of compensation and related costs for executive and administrative personnel, fees for legal and other professional services, depreciation of equipment and software used for general corporate purposes and amortization of intangible assets.
Goodwill	Goodwill Goodwill represents the excess of the fair value of consideration given over the fair value of the tangible assets, identifiable intangible assets and liabilities assumed in a business combination. We are required to test goodwill for impairment annually and whenever events or circumstances indicate the fair value of a reporting unit may be below its carrying value. Goodwill is reviewed for impairment annually on October 1. A reporting unit is the operating segment or a business that is one level below that operating segment. Reporting units are aggregated as a single reporting unit if they have similar economic characteristics. We aggregated our reporting units into a single reporting unit because we determined they have similar economic characteristics. There was no impairment to our goodwill related to our acquisitions. Goodwill is reviewed for impairment annually on October 1 st
Impairment of Long-Lived Assets and Intangible Assets	Impairment of Long-Lived Assets and Intangible Assets Long-lived assets including intangible assets with finite useful lives are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell. Intangible assets that have indefinite useful lives are not amortized but, instead, tested at least annually for impairment while intangible assets that have finite useful lives continue to be amortized over their respective useful lives.
Income Taxes	Income Taxes We account for income taxes in accordance with Financial Accounting Standards Board (“FASB”) ASC Topic No. 740, Income Taxes (“ASC 740”), which requires that deferred tax assets and liabilities be recognized using enacted tax rates for the effect of temporary differences between the book and tax basis of recorded assets and liabilities. ASC 740 also requires that deferred tax assets be reduced by a valuation allowance if it is more likely than not that some or all of the net deferred tax assets will not be realized. We record a valuation allowance to reduce our gross deferred tax assets to the amount that is more likely than not (a likelihood of more than 50 percent) to be realized. In order for us to realize our deferred tax assets, we must be able to generate sufficient taxable income. We evaluate the appropriateness of our deferred tax assets and related valuation allowance in accordance with ASC 740 based on all available positive and negative evidence. As of December 31, 2016 and 2015 we do not have any valuation allowance recorded to reduce our gross deferred tax assets as we believe we have met the more likely than not threshold we will realize our tax loss carry-forwards in the foreseeable future.
Internet Advertising	Internet Advertising We recognize Internet advertising expense based on the specifics of the individual agreements. Under partner and affiliate agreements, third parties refer prospects to our web site, and we pay the third parties when the customer completes the customer registration process, or in some cases, upon the first successful billing of a customer. We record these expenses on a monthly basis as prospects are successfully converted to customers. Under Internet search advertising, we record expenses based on actual “click activity” on our displayed advertisements following targeted key word searches.
Inventories	Inventories Inventories consist of finished products sold through our supplies store and are accounted for using the lower of cost (first-in, first-out method) or market. Inventories reported as a component of other current assets in both 2016 and 2015 were $3.5 million.
Net Income (loss) per Share	Net Income (loss) per Share Net income (loss) per share represents net income (loss) attributable to common stockholders divided by the weighted average number of common shares outstanding during a reported period. The diluted net income (loss) per share reflects the potential dilution that could occur if securities or other contracts to issue common stock, including stock options, (commonly and hereafter referred to as “common stock equivalents”), were exercised or converted into common stock. Diluted net income (loss) per share is calculated by dividing net income (loss) during a reported period by the sum of the weighted average number of common shares outstanding plus common stock equivalents for the period. The following table reconciles share amounts utilized to calculate basic and diluted net income (loss) per share (in thousands, except per share data): Year Ended December 31, 2016 2015 2014 Net income (loss) $ 75,229 $ (4,198 ) $ 36,882 Basic - weighted average common shares 17,245 16,436 16,011 Dilutive effect of common stock equivalents 1,006 — (1) 406 Diluted - weighted average common shares 18,251 16,436 16,417 Earnings (loss) per share: Basic $ 4.36 $ (0.26 ) $ 2.30 Diluted $ 4.12 $ (0.26 ) $ 2.25 (1) Common stock equivalents are excluded from the diluted net loss per share calculation as their effect is anti-dilutive. The shares related to the 2015 contingent consideration are not included because they are anti-dilutive. The calculation of dilutive shares excludes the effect of the following options that are considered anti-dilutive (in thousands): Year ended December 31, 2016 2015 2014 Anti-dilutive stock options 211 3,596 134
Property and Equipment	Property and Equipment We account for property and equipment at cost less accumulated depreciation and amortization. We compute depreciation using the straight-line method over the estimated useful life of the asset, generally three to five years for furniture, fixtures and equipment and ten to forty years for building and building improvements. We have a policy of capitalizing expenditures that materially increase assets’ useful lives and charging ordinary maintenance and repairs to operations as incurred. When property or equipment is disposed of, the cost and related accumulated depreciation and amortization are removed, and any gain or loss is included in operations.
Research and Development Costs	Research and Development Costs Research and development expense principally consists of compensation and related expenses for personnel involved in the development of our services, depreciation of equipment and software and expenditures for consulting services and third party software.
Revenue Recognition	Revenue Recognition We recognize revenue from product sales or services rendered, as well as commissions from advertising or sale of products by third party vendors to our customer base when the following four revenue recognition criteria are met: persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, the selling price is fixed or determinable, and collectability is reasonably assured. We earn service revenue in several different ways: (1) customers may pay us a monthly fee based on a subscription plan; (2) customers may qualify under our USPS partnership to have their service fees waived or refunded and then we are compensated directly by the USPS; (3) we may earn transaction related revenue based on customers purchasing postage or printing shipping labels; (4) we may earn compensation by offering customers a discounted postage rate that is provided to the customers by our integration partners; and (5) we may earn other types of revenue shares or other compensation from specific customers or integration partner, and is recognized in the period that services are provided. Customers purchase postage from the USPS through our mailing and shipping solutions. Postage purchase funds that are transferred directly from the customers to the USPS are not recognized as revenue for this postage, as it is purchased by our customers directly from the USPS. Customized postage revenue, which includes the face value of postage, from the sale of PhotoStamps and PictureItPostage sheets and rolls is made pursuant to a sales contract that provides for transfer of both title and risk of loss upon our delivery to the carrier and revenue is recognized at that time. On a limited basis, we allow third parties to offer products and promotions to our customer base. These arrangements generally provide payment in the form of a flat fee or revenue sharing arrangements where we receive payment upon customers accessing third party products and services. Total revenue from such advertising arrangements was not significant during 2016, 2015 and 2014. We provide our customers with the opportunity to purchase parcel insurance directly through our solutions. Insurance revenue represents the gross amount charged to the customer for purchasing insurance and the related cost represents the amount paid to our insurance providers. We recognize revenue on insurance purchases upon the ship date of the insured package.
Sales and Marketing	Sales and Marketing Sales and marketing expense principally consists of spending to acquire new customers and compensation and related expenses for personnel engaged in sales, marketing, and business development activities. Ongoing marketing programs include the following: traditional advertising, partnerships, customer referral programs, customer re-marketing efforts, telemarketing, direct sales, direct mail, and online advertising.
Segment Information	Segment Information We operate in a single reportable segment, “Internet Mailing and Shipping Solutions.” Operating segments are defined as components of an enterprise for which discrete financial information is available that is evaluated regularly by the chief operating decision maker ("CODM") for purposes of allocating resources and evaluating financial performance. In 2015, we completed the reassessment of our segment reporting in light of our Endicia acquisition. Based on this reassessment, we identified two operating segments Segment Reporting The primary purpose of the CODM reviewing Endicia’s financial information was to inform resource allocation decisions relating to achieving potential acquisition related synergies including the following areas: (1) cost reductions for compensation and related expenses associated with duplicative personnel; (2) the planned level of sales and marketing spend; and (3) cost reductions from elimination of duplicative operational expenses and vendors. In 2016, we substantially realized the previously identified synergies and merged Endicia’s operations and employee groups into the existing consolidated structure which resulted in the CODM no longer needing to review Endicia’s performance and financial information separately. As a result, the Company's CODM now reviews the financial information presented on a consolidated basis for purposes of allocating resources and evaluating performance. Based on our evaluation in accordance with ASC 280, including consideration of the ShippingEasy acquisition, we concluded that we had one operating segment in 2016. In 2014, all of our operations, revenue and assets were within the United States. In 2015 and 2016, primarily as a result of our Endicia acquisition, we had international revenue and assets that were less than 1% of total revenue and assets with the remainder in the United States. During 2016, 2015 and 2014, we did not recognize revenue from any one customer that represented 10% or more of revenues.
Short-Term Financing Obligations	Short- Term Financing Obligations We utilize short-term financing, which is separate from our debt as described in Note – 7 “Debt,”
Stock-Based Compensation	Stock-Based Compensation We estimate the fair value of share-based payment awards on the date of grant using an option-pricing model and recognize stock-based compensation expense during each period based on the value of that portion of share-based payment awards that is ultimately expected to vest during the period, reduced for estimated forfeitures. We estimate forfeitures at the time of grant based on historical data and revise, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Compensation expense recognized for all employee stock options granted is recognized using the straight-line method over their respective vesting periods of up to five years. Starting in the third quarter of 2016, our stock-based compensation expense included performance based inducement equity awards relating to the ShippingEasy acquisition as described in Note 3 - Acquisitions The following table sets forth the stock-based compensation expense that we recognized for the periods indicated (in thousands): 2016 2015 2014 Stock-based compensation expense relating to: Employee and director stock options $ 32,891 $ 16,644 $ 4,473 Employee stock purchases 1,058 582 326 Total stock-based compensation expense $ 33,949 (2) $ 17,226 (1) $ 4,799 Stock-based compensation expense relating to: Cost of revenues $ 1,828 $ 995 $ 402 Sales and marketing 7,194 4,549 955 Research and development 6,633 3,149 998 General and administrative 18,294 8,533 2,444 Total stock-based compensation expense $ 33,949 (2) $ 17,226 (1) $ 4,799 (1) Included in this amount is $1.3 million of stock-based compensation expense relating to the change in the fair value of our contingent consideration liability in connection with our acquisition of ShipStation. See Note - 3 “Acquisitions.” (2) Included in this amount is $1.9 million of stock-based compensation expense relating to performance based equity awards granted in connection with our acquisition of ShippingEasy. See Note - 3 “Acquisitions.” We use the Black-Scholes-Merton option valuation model to estimate the fair value of share-based payment awards on the date of grant, which requires us to make a number of highly complex and subjective assumptions, including stock price volatility, expected term, risk-free interest rates and projected employee stock option exercise behaviors. In the case of options we grant, our assumption of expected volatility is based on the historical volatility of our stock price over the term equal to the expected life of the options. We base the risk-free interest rate on U.S. Treasury zero-coupon issues with a remaining term equal to the expected life of the options assumed at the date of grant. The estimated expected life represents the weighted-average period the stock options are expected to remain outstanding, determined based on an analysis of historical exercise behavior. The following are the weighted average assumptions used in the Black-Scholes valuation model for the periods indicated: 2016 2015 2014 Expected dividend yield — — — Risk-free interest rate 0.99 % 1.00 % 0.87 % Expected volatility 48 % 46 % 50 % Expected life (in years) 3.4 3.4 3.5 Expected forfeiture rate 6 % 6 % 6 % We elected to utilize the alternative transition method for calculating the tax effects of stock-based compensation. The alternative transition method includes computational guidance to establish the beginning balance of the additional paid-in capital pool (“APIC Pool”) related to the tax effects of employee stock-based compensation, and a simplified method to determine the subsequent impact on the APIC Pool for employee stock-based compensation awards that are vested and outstanding upon adoption of FASB ASC Topic No. 718 Compensation – Stock Compensation (“ASC 718”). A tax benefit will be recorded in additional paid-in capital when these deductions reduce our future income taxes payable.
Trademarks, Patents and Intangible Assets	Trademarks, Patents and Intangible Assets Acquired trademarks, patents and other intangibles include both amortizable and non-amortizable assets and are included in intangible assets, net in the accompanying consolidated balance sheets. Intangible assets are carried at cost less accumulated amortization. Cost associated with internally developed intangible assets is typically expensed as incurred as research and development costs. Amortization of amortizable intangible assets is calculated on a straight-line basis, which is consistent with the expected future cash flows.
Treasury Stock	Treasury During 2016 and 2014, we repurchased approximately 844,000 shares and 435,000 shares for $80.6 million and $12.9 million, respectively. We did not repurchase shares in 2015.
Website Development Costs	Website Development Costs We develop and maintain our website. Costs associated with the operation of our website consist primarily of software and hardware purchased from third parties and administrative costs relating to the maintenance and development of the website. Costs related to the purchase of software and hardware are capitalized based on our property and equipment capitalization policy. These capitalized costs are amortized based on their estimated useful life. Administrative costs related to the maintenance and development of our website are expensed as incurred.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the FASB issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers ("ASU 2014-09") an updated standard on revenue recognition. This ASU will supersede the revenue recognition requirements in Accounting Standards Codification Topic 605, Revenue Recognition, and most industry-specific guidance. ASU 2014-09 provides enhancements to the quality and consistency of how revenue is reported while also improving comparability in the financial statements of companies reporting using US GAAP and International Financial Reporting Standards. The core principle of the new standard is for companies to recognize revenue to depict the transfer of goods or services to customers in amounts that reflect the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so the companies may be required to use more judgment and make more estimates than under current authoritative guidance. ASU 2014-09 will be effective for the Company in the first quarter of fiscal 2018 and may be applied on a full retrospective or modified retrospective approach. The Company has reviewed the ASU 2014-09 updated standard on revenue recognition. The Company is currently in the process of reviewing its material contracts to assess the impact of the new standard. While the Company has performed a review of the impact on certain contracts, it has not completed a review of all material contracts. As a result, the Company is currently still in the process of evaluating the adoption method and the impact the adoption of this standard will have on its consolidated financial statements. In February 2016, the FASB issued a new accounting standard for leases. The new standard generally requires the recognition of financing and operating lease liabilities and corresponding right-of-use assets on the balance sheet. For financing leases, a lessee recognizes amortization of the right-of-use asset as an operating expense over the lease term separately from interest on the lease liability. For operating leases, a lessee recognizes its total lease expense as an operating expense over the lease term. The amendments are effective for the Company in the first quarter of 2019 using a modified retrospective approach with early adoption permitted. The Company is currently evaluating the impact the adoption of this standard will have on its consolidated financial statements. In March 2016, the FASB simplified certain areas of accounting for stock-based compensation, including accounting for the income tax consequences of stock-based compensation, determining the classification of awards as either equity or liabilities, classifying certain items within the statement of cash flows and introducing an accounting policy election to account for forfeitures of non-vested awards as they occur. The simplified guidance is effective for the Company in the first quarter of 2017. Depending on the area simplified, the guidance is effective either prospectively, retrospectively or using a modified retrospective approach. Early adoption is permitted. The adoption of this standard will not have a material impact on our consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, a standard which simplifies the accounting for goodwill impairment. The guidance removes Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. Goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The revised guidance will be applied prospectively, and is effective for the Company in the first quarter of 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company is evaluating the effect this new standard will have on its financial statements.

Summary of Significant Accoun23

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Summary of Significant Accounting Policies [Abstract]
Calculation of Basic and Diluted Net Income Per Share	The following table reconciles share amounts utilized to calculate basic and diluted net income (loss) per share (in thousands, except per share data): Year Ended December 31, 2016 2015 2014 Net income (loss) $ 75,229 $ (4,198 ) $ 36,882 Basic - weighted average common shares 17,245 16,436 16,011 Dilutive effect of common stock equivalents 1,006 — (1) 406 Diluted - weighted average common shares 18,251 16,436 16,417 Earnings (loss) per share: Basic $ 4.36 $ (0.26 ) $ 2.30 Diluted $ 4.12 $ (0.26 ) $ 2.25 (1) Common stock equivalents are excluded from the diluted net loss per share calculation as their effect is anti-dilutive. The shares related to the 2015 contingent consideration are not included because they are anti-dilutive.
Anti-Dilutive Securities Excluded from Computation of Earnings Per Share	The calculation of dilutive shares excludes the effect of the following options that are considered anti-dilutive (in thousands): Year ended December 31, 2016 2015 2014 Anti-dilutive stock options 211 3,596 134
Stock-Based Compensation Expense	The following table sets forth the stock-based compensation expense that we recognized for the periods indicated (in thousands): 2016 2015 2014 Stock-based compensation expense relating to: Employee and director stock options $ 32,891 $ 16,644 $ 4,473 Employee stock purchases 1,058 582 326 Total stock-based compensation expense $ 33,949 (2) $ 17,226 (1) $ 4,799 Stock-based compensation expense relating to: Cost of revenues $ 1,828 $ 995 $ 402 Sales and marketing 7,194 4,549 955 Research and development 6,633 3,149 998 General and administrative 18,294 8,533 2,444 Total stock-based compensation expense $ 33,949 (2) $ 17,226 (1) $ 4,799 (1) Included in this amount is $1.3 million of stock-based compensation expense relating to the change in the fair value of our contingent consideration liability in connection with our acquisition of ShipStation. See Note - 3 “Acquisitions.” (2) Included in this amount is $1.9 million of stock-based compensation expense relating to performance based equity awards granted in connection with our acquisition of ShippingEasy. See Note - 3 “Acquisitions.”
Weighted Average Assumptions Used in Black-Scholes Valuation Model	The following are the weighted average assumptions used in the Black-Scholes valuation model for the periods indicated: 2016 2015 2014 Expected dividend yield — — — Risk-free interest rate 0.99 % 1.00 % 0.87 % Expected volatility 48 % 46 % 50 % Expected life (in years) 3.4 3.4 3.5 Expected forfeiture rate 6 % 6 % 6 %

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2016
ShippingEasy [Member]
Business Acquisition [Line Items]
Allocation of the Purchase Price	The following table is the final allocation of the purchase price (in thousands, except years): Fair Value Fair Value Useful Life (In Years) Weighted Average Estimated Useful Life (In Years) Trade accounts receivable $ 1,194 Other assets 76 Property and equipment 40 Goodwill 40,953 Identifiable intangible assets: Trade name $ 1,304 8 Developed technology 6,948 5 Customer relationships 6,316 5 Non-compete agreements 1,111 3 to 5 Total identifiable intangible assets 15,679 5 Accrued expenses and other liabilities (707 ) Deferred revenue (185 ) Deferred tax liability (1,603 ) Total purchase price 55,447 Less: settlement of preexisting relationship (accounts receivable) 1,194 Purchase price, net of settlement $ 54, 253
Pro Forma Financial Information	The following table presents the pro-forma financial information (in thousands, except per share amounts) and assumes the acquisition of ShippingEasy occurred on January 1, 2015: Year Ended December 31, 2016 2015 Revenues $ 370,560 $ 219,426 Income (loss) from operations 121,537 (9,138 ) Net income (loss) 75,810 (6,608 ) Basic earnings (loss) per share $ 4.40 $ (0.40 ) Diluted earnings (loss) per share $ 4.15 $ (0.40 ) (1)
Endicia [Member]
Business Acquisition [Line Items]
Allocation of the Purchase Price	The following table sets forth the final allocation of the purchase price (in thousands, except years): Fair Value Fair Value Useful Life (In Years) Weighted Average Estimated Useful Life (In Years) Trade accounts receivable $ 10,247 Other assets 771 Property and equipment 2,798 Goodwill 131,860 Identifiable intangible assets: Trade name $ 10,900 Indefinite Developed technology 26,100 9 Customer relationships 43,200 6 Total identifiable intangible assets 80,200 7 Accrued expenses and other liabilities (10,212 ) Deferred revenue (926 ) Total purchase price $ 214,738
Pro Forma Financial Information	The following table presents the pro-forma financial information (in thousands, except per share amounts) and assumes the acquisition of Endicia occurred on January 1, 2014: Year Ended December 31, 2015 2014 Revenue $ 273,055 $ 204,628 (Loss) income from operations (7,657 ) 20,820 Net (loss) income (9,273 ) 32,536 (1) Basic (loss) earnings per share $ (0.58 ) $ 2.03 Diluted (loss) earnings per share $ (0.58 ) (2) $ 1.98 (1) Pro-forma net income of $32.5 million in 2014 includes valuation allowance releases of $13.6 million. (2) Common stock equivalents are excluded from the diluted net loss per share calculation as their effect is anti-dilutive.
ShipWorks [Member]
Business Acquisition [Line Items]
Schedule of Purchase Price	The total purchase price for ShipWorks was approximately $22.1 million and was comprised of the following (in thousands): Fair Value Cash consideration $ 21,952 Deferred consideration 181 Total purchase price $ 22,133
Allocation of the Purchase Price	The following table sets forth the final allocation of the purchase price (in thousands, except years): Fair Value Fair Value Useful Life (In Years) Weighted Average Estimated Useful Life (In Years) Cash and cash equivalents $ 803 Trade accounts receivable 353 Other assets 21 Property and equipment 1,091 Goodwill 16,349 Identifiable intangible assets: Trademark $ 200 6 Developed technology 1,700 7 Non-compete agreement 700 4 Customer relationship 2,300 6 Total identifiable intangible assets 4,900 6 Accrued expenses and other liabilities (1,119 ) Deferred revenue (265 ) Total purchase price $ 22,133
ShipStation [Member]
Business Acquisition [Line Items]
Schedule of Purchase Price	The total purchase price for ShipStation was approximately $66.2 million and was comprised of the following (in thousands, except shares): Fair Value Cash consideration $ 50,000 Fair value of performance linked earn-out of up to 768,900 shares of Stamps.com common stock (contingent consideration) 16,242 Total purchase price $ 66,242
Allocation of the Purchase Price	The following table is the allocation of the purchase price (in thousands, except years): Fair Value Fair Value Useful Life Weighted Average Estimated Useful Life (In Years) Cash and cash equivalents $ 1,117 Trade accounts receivable 254 Other assets 39 Property and equipment 187 Goodwill 50,544 Identifiable intangible assets: Trademark $ 500 4 Developed technology 5,300 8 Non-compete agreement 400 4 Customer relationship 9,000 8 Total identifiable intangible assets 15,200 8 Accrued expenses and other liabilities (835 ) Deferred revenue (264 ) Total purchase price $ 66,242
ShipStation and ShipWorks [Member]
Business Acquisition [Line Items]
Pro Forma Financial Information	The following table presents the pro-forma financial information (in thousands, except per share amounts) and assumes the acquisition of ShipStation and ShipWorks occurred on January 1, 2013. Contingent consideration charge of approximately $8.8 million recognized in 2014 is excluded from the pro-forma information below: Year Ended December 31, 2014 2013 Revenue $ 154,459 $ 137,626 Income from operations 32,873 33,208 Net income 32,342 56,691 (1) Basic earnings per share $ 2.02 $ 3.61 Diluted earnings per share $ 1.97 $ 3.48 (1) Pro-forma net income of $56.7 million in 2013 includes valuation allowance releases of $13.6 million and $9.7 million recognized in 2014 and 2013, respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets [Abstract]
Schedule of Goodwill	The following tables summarize goodwill as of December 31, 2015 and 2016 (in thousands): 2015 Goodwill balance at December 31, 2014 $ 66,893 Acquisitions (see Note 3 – “Acquisitions” 130,914 Goodwill balance at December 31, 2015 $ 197,807 2016 Goodwill balance at December 31, 2015 $ 197,807 Purchase price adjustment (see Note 3 – “Acquisitions” 945 Acquisition of ShippingEasy (see Note 3 – “Acquisitions” 40,953 Goodwill balance at December 31, 2016 $ 239,705
Schedule of Acquired Intangible Assets	The following table summarizes our amortizable intangible assets as of December 31, 2016 (in thousands): Gross Carrying Amount Accumulated Amortization Net Carrying Amount Patents and Others $ 8,889 $ 8,774 $ 115 Customer Relationships 60,816 12,199 48,617 Technology 40,048 6,100 33,948 Non-Compete 2,211 777 1,434 Trademark 2,004 479 1,525 Total amortizable intangible assets at December 31, 2016 $ 113,968 $ 28,329 $ 85,639 The following table summarizes our amortizable intangible assets as of December 31, 2015 (in thousands): Gross Carrying Amount Accumulated Amortization Net Carrying Amount Patents and Others $ 8,889 $ 8,729 $ 160 Customer Relationships 54,500 2,773 51,727 Technology 33,100 1,598 31,502 Non-Compete 1,100 389 711 Trademark 700 239 461 Total amortizable intangible assets at December 31, 2015 $ 98,289 $ 13,728 $ 84,561
Schedule of Future Amortization Expense	Our estimated amortization expense for the next five years and thereafter is as follows (in thousands): Year Ending December 31, Estimated Amortization Expense 2017 $ 16,038 2018 15,854 2019 15,608 2020 15,440 2021 13,040 Thereafter 9,659 Total $ 85,639

Cash, Cash Equivalents and In26

Cash, Cash Equivalents and Investments (Tables)	12 Months Ended
	Dec. 31, 2016
Cash, Cash Equivalents and Investments [Abstract]
Cash, Cash Equivalents, Restricted Cash and Investments	The following tables summarize our cash, cash equivalents, and investments as of December 31, 2016 and 2015 (in thousands): December 31, 2016 Cost or Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and cash equivalents: Cash $ 101,987 — — $ 101,987 Money market 4,945 — — 4,945 Total cash and cash equivalents 106,932 — — 106,932 Short-term investments: Corporate bonds and asset backed securities 1,500 13 (2 ) 1,511 Total short-term investments 1,500 13 (2 ) 1,511 Long-term investments: Corporate bonds and asset backed securities — — — — Total long-term investments — — — — Cash, cash equivalents and investments $ 108,432 13 (2 ) $ 108,443 December 31, 2015 Cost or Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and cash equivalents: Cash $ 63,593 — — $ 63,593 Money market 1,533 — — 1,533 Total cash and cash equivalents 65,126 — — 65,126 Short-term investments: Corporate bonds and asset backed securities 8,549 7 (3 ) 8,553 Total short-term investments 8,549 7 (3 ) 8,553 Long-term investments: Corporate bonds and asset backed securities 1,515 17 (3 ) 1,529 Total long-term investments 1,515 17 (3 ) 1,529 Cash, cash equivalents and investments $ 75,190 24 (6 ) $ 75,208
Contractual Maturities of Marketable Fixed-Income Securities	The following table summarizes contractual maturities of our marketable fixed-income securities as of December 31, 2016 (in thousands): Amortized Cost Estimated Fair Value Due within one year $ 1,500 $ 1,511 Due after one year — — Total $ 1,500 $ 1,511

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Measurements [Abstract]
Financial Assets Measured at Fair Value on a Recurring Basis	The following tables summarize our financial assets measured at fair value on a recurring basis as of December 31, 2016 and 2015 (in thousands): Fair Value Measurement at Reporting Date Using Description December 31, 2016 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 106,932 $ 106,932 $ — $ — Available-for-sale debt securities 1,511 — 1,511 — Total $ 108,443 $ 106,932 $ 1,511 $ — Fair Value Measurement at Reporting Date Using Description December 31, 2015 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 65,126 $ 65,126 $ — $ — Available-for-sale debt securities 10,082 — 10,082 — Total $ 75,208 $ 65,126 $ 10,082 $ —
Contingent Consideration Measured at Fair Value on a Recurring Basis	The following table summarizes our contingent consideration measured at fair value on a recurring basis (in thousands): Fair Value Measurement at Reporting Date Using Description December 31, 2015 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Contingent consideration – current $ 63,209 $ 63,209 $ — $ —
Reconciliation of Contingent Consideration Obligation	The following table represents a reconciliation of contingent consideration obligation measured on a recurring basis using significant unobservable inputs (level 3) as of December 31, 2014 and then transferred to quoted prices in active markets (level 1) as of December 31, 2015 (in thousands): 2015 Beginning of year balance $ 25,015 Contingent consideration distribution (9,225 ) Contingent consideration charges (1) 46,088 Contingent consideration compensation expense (1) 1,331 End of year balance $ 63,209 (1) This amount represents fair value adjustment during the year to contingent consideration recorded associated with the acquisition of ShipStation. The $46.1 million contingent consideration charge is recorded as a separate line item in our consolidated statement of income. The $1.3 million contingent consideration charge relating to certain employees is recorded in general and administrative expense in operating expense. See Note 3 – “Acquisitions” for further description. At December 31, 2015, the contingent consideration obligation was transferred from level 3 to level 1.

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2016
Debt [Abstract]
Schedule of Maturities of our Debt Obligations	The contractual maturities of our debt obligations due subsequent to December 31, 2016 are as follows (in thousands): Amount 2017 $ 6,703 2018 8,766 2019 10,828 2020 122,521 2021 — Total debt 148,818 Less debt issuance costs 1,465 Total debt, net of debt issuance costs $ 147,353

Accounts Payable and Accrued 29

Accounts Payable and Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2016
Accounts Payable and Accrued Expenses [Abstract]
Accounts Payable and Accrued Expenses	The following table summarizes our accounts payable and accrued expenses as of December 31, 2016 and 2015 (in thousands): 2016 2015 Payroll and related accrual $ 15,168 $ 12,863 Cost of revenue, inventory and materials accrual 977 539 Construction and facility expense accrual 1,899 649 Professional fees accrual 3,802 1,973 Sales and marketing related accrual 6,001 5,145 Operating expenses related accrual 35,285 15,613 Short-term financing obligations 15,554 13,313 Other accruals 7,519 10,721 Accounts payable and accrued expenses $ 86,205 $ 60,816

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2016
Property and Equipment [Abstract]
Property and Equipment	Property and equipment is summarized as follows (in thousands): 2016 2015 Land $ 7,156 $ 7,156 Building 4,886 4,886 Building improvements 17,705 14,048 Leasehold improvements 2,003 1,055 Furniture and equipment 2,509 2,016 Computers and software 22,740 18,920 56,999 48,081 Less accumulated depreciation and amortization (20,170 ) (16,374 ) Property and equipment, net $ 36,829 $ 31,707

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Taxes [Abstract]
Reconciliation of Total Amounts of Unrecognized Tax Benefits	The following is a tabular reconciliation of the total amounts of unrecognized tax benefits for the years ended December 31, 2016, 2015 and 2014 (in thousands): Unrecognized Tax Benefits Balance at December 31, 2013 $ (2,314 ) Addition for tax positions of prior years (2,349 ) Addition for tax position of the current year (560 ) Settlement — Balance at December 31, 2014 $ (5,223 ) Addition for tax positions of prior years (251 ) Addition for tax position of the current year (560 ) Settlement — Balance at December 31, 2015 $ (6,034 ) Additions for tax positions of prior years (810 ) Reduction for tax positions of prior years 2,596 Additions for tax position of the current year (2,156 ) Settlement 251 Balance at December 31, 2016 $ (6,153 )
Deferred Tax Assets and Liabilities	The tax effect of temporary differences that give rise to a significant portion of the deferred tax assets and liabilities at December 31, 2016 and 2015 are presented below (in thousands): 2016 2015 Deferred tax assets: Net operating loss carryforward $ 3,406 $ 22,024 Tax credit carryforwards 16,091 6,872 Definite lived intangibles 200 2,946 Contingent consideration 20,461 20,742 Stock compensation 12,162 4,800 Accruals 7,771 3,534 Deferred tax assets 60,091 60,918 Deferred tax liabilities: Fixed assets (726 ) (464 ) Indefinite lived intangibles (7,770 ) (1,922 ) Federal benefit of state tax deferred tax assets (2,813 ) (1,308 ) Deferred tax liabilities (11,309 ) (3,694 ) Net deferred tax assets $ 48,782 $ 57,224
Provision for Income Taxes	The income tax expense (benefit) consists of (in thousands): 2016 2015 2014 Current: Federal $ 2,400 $ 806 $ 730 State 5,722 611 127 8,122 1,417 857 Deferred: Federal 11,023 (596 ) (14,286 ) State (3,403 ) (1,341 ) 652 Adjustment for change in tax rate (781 ) (1,471 ) 80 APIC charge on excess tax benefits 26,784 618 — 33,623 (2,790 ) (13,554 ) Income tax expense (benefit) $ 41,745 $ (1,373 ) $ (12,697 )
Differences Between Provision for Income Taxes and Income Taxes at Statutory Federal Income Tax Rate	Differences between the benefit for income taxes and income taxes at the statutory federal income tax rate are as follows (in thousands): 2016 2015 2014 Income tax at statutory federal rate $ 40,941 $ (1,950 ) $ 8,223 State tax – net of federal benefit 4,127 (2 ) 290 Stock-based compensation 2,757 851 497 Nondeductible items 485 902 15 Research and development (1,963 ) — — Uncertain tax positions (2,048 ) 173 1,767 Change in tax rate (781 ) (1,471 ) 80 Change in valuation allowance — — (13,554 ) Other changes in valuation allowance, net — — (11,480 ) Other, net (1,773 ) 124 1,465 $ 41,745 $ (1,373 ) $ (12,697 )

Employee Stock Plans (Tables)

Employee Stock Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Employee Stock Plans [Abstract]
Stock Option Activity	A summary of stock option activity is as follows (in thousands, except per share amounts): Options Outstanding Weighted Average Exercise Price per Share Number of Options Balance at December 31, 2013 996 $ 18.12 Granted 2,251 32.55 Forfeited (75 ) 35.96 Exercised (203 ) 16.34 Balance at December 31, 2014 2,969 $ 28.91 Granted 694 65.96 Forfeited (98 ) 37.43 Exercised (459 ) 23.73 Balance at December 31, 2015 3,106 $ 37.75 Granted 816 91.36 Forfeited (198 ) 72.72 Exercised (432 ) 30.04 Balance at December 31, 2016 3,292 $ 49.95 The following table summarizes stock option activity for 2016: Number of Stock Options (in thousands) Weighted Average Exercise Price Weighted Average Remaining Contractual Life (in years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2015 3,106 $ 37.75 Granted 816 91.36 Exercised (432 ) 30.04 Forfeited or expired (198 ) 72.72 Balance at December 31, 2016 3,292 $ 49.95 7.9 $ 213,066 Exercisable at December 31, 2016 1,711 $ 35.14 7.2 $ 136,056
Weighted-Average Fair Value of Stock Grants	The weighted-average fair value of stock options granted for 2016, 2015 and 2014 using the Black-Scholes valuation method are as follows: 2016 2015 2014 Weighted-average fair value of stock options with an exercise price equal to the market price on the grant date $ 32.27 $ 23.19 $ 11.87 Weighted-average fair value of stock options with an exercise price greater than the market price on the grant date — — — Total $ 32.27 $ 23.19 $ 11.87
Weighted Average Exercise Prices for Stock Options Exercised	Weighted average exercise prices for stock options exercised in 2016 are as follows: 2016 Weighted-average exercise price of stock options with an exercise price equal to the market price on the grant date $ 30.04 Weighted-average exercise price of stock options with an exercise price greater than the market price on the grant date — Total weighted-average exercise price $ 30.04
Outstanding and Exercisable Options	The following tables summarize information concerning outstanding and exercisable options at December 31, 2016 (in thousands, except numbers of years and per share amounts): Options Outstanding Options Exercisable Range of Exercise Prices Number Outstanding Weighted Average Remaining Contractual Life (in Years) Weighted Average Exercise Price per Share Number Exercisable Weighted Average Exercise Price per Share $0.00 - $9.99 18 2.3 $ 9.12 18 $ 9.12 $10.00 - $19.99 197 4.0 12.62 197 12.62 $20.00 - $29.99 89 6.0 26.17 79 25.83 $30.00 - $39.99 1,649 7.7 32.57 1,132 32.59 $40.00 - $49.99 72 7.6 45.23 43 45.06 $50.00 - $59.99 122 8.2 58.25 68 58.25 $60.00 - $69.99 216 8.3 66.00 77 66.12 $70.00 - $79.99 256 8.8 73.73 72 72.25 $80.00 - $89.99 266 9.2 87.24 — — $90.00 - $99.99 361 9.4 94.51 22 91.86 $100.00 - $109.99 42 9.6 104.11 3 101.32 $120.00 - $129.99 5 9.2 122.25 — — $0.00 - $129.99 3,293 7.9 $ 49.95 1,711 $ 35.14
Non-Vested Stock Options	The following table summarizes the status of our non-vested stock options as of December 31, 2016: Non-vested Number of Stock Options (in thousands) Weighted Average Grant Date Fair Value per Option Non-vested at December 31, 2015 1,900 $ 29.62 Granted 816 32.37 Vested (1,092 ) 30.68 Forfeited / Cancelled (42 ) 21.65 Non-vested at December 31, 2016 1,582 $ 30.35

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies [Abstract]
Future Minimum Lease Payment Under Operating Leases	The following table is a schedule of our significant contractual obligations and commercial commitments (other than debt commitments, which are summarized in Note 7- “Debt” Twelve Month Period Ending December 31, Operating Lease Obligations 2017 $ 4,048 2018 3,563 2019 1,369 2020 1,396 2021 1,052 Thereafter — Total $ 11,428

Quarterly Information (Unaudi34

Quarterly Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Information (Unaudited) [Abstract]
Quarterly Information	Quarter Ended March June September (3) December (2) (in thousands except per share data) Fiscal Year 2016: Revenues $ 81,837 $ 84,013 $ 92,559 $ 105,896 Gross profit 67,215 70,293 75,832 87,993 Income from operations 22,219 24,967 31,591 41,443 Net income 13,238 14,291 18,672 29,028 Net income per share: Basic $ 0.76 $ 0.82 $ 1.08 $ 1.71 Diluted $ 0.71 $ 0.79 $ 1.03 $ 1.61 Weighted average shares outstanding: Basic 17,357 17,384 17,218 17,018 Diluted 18,664 18,192 18,120 18,026 Fiscal Year 2015: Revenues $ 44,052 $ 48,360 $ 51,669 $ 69,876 Gross profit 34,427 38,422 40,480 56,693 Income (loss) from operations (2,159 ) (15,152 ) 12,991 (1,000 ) Net (loss) income (970 ) (10,431 ) 7,274 (71 ) Net (loss) income per share: Basic $ (0.06 ) $ (0.64 ) $ 0.44 $ (0.00 ) Diluted $ (0.06 ) $ (0.64 ) $ 0.42 $ (0.00 ) Weighted average shares outstanding: Basic 16,156 16,402 16,538 16,642 Diluted 16,156 (1) 16,402 (1) 17,517 16,642 (1) (1) Common stock equivalents are excluded from the diluted earnings per share calculation as their effect is anti-dilutive. (2) The fourth quarter results of 2015 include the impact of the Company’s acquisition of Endicia. (3) The third and fourth quarter results of 2016 include the impact of the Company’s acquisition of ShippingEasy.

Summary of Significant Accoun35

Summary of Significant Accounting Policies, Principles of Consolidation through Property and Equipment (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended														12 Months Ended
	Dec. 31, 2016		Sep. 30, 2016	[2]	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015		Sep. 30, 2015	[2]	Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014	Jul. 02, 2016	Nov. 30, 2015	Aug. 29, 2014	Jun. 10, 2014
Accounts Receivable [Abstract]
Allowances for uncollectible accounts	$ 1,188						$ 831								$ 1,188	$ 831		$ 414
Increase in allowance for doubtful accounts															356	417		131
Advertising Costs [Abstract]
Advertising and tradeshow costs															12,100	10,800		9,700
Fair Value of Financial Instruments [Abstract]
Charges relating to contingent consideration liability																47,400
Contingent consideration charges															0	46,088		8,438
Marketing, research and development in operating expenses																1,300
Contingent consideration liability							63,200									63,200
Goodwill [Abstract]
Goodwill impairment															$ 0
Income tax [Abstract]
Percentage of realization of deferred tax assets, minimum	50.00%														50.00%
Inventories [Abstract]
Inventories	$ 3,500						3,500								$ 3,500	3,500
Net Income per Share [Abstract]
Net income (loss)	$ 29,028	[1]	$ 18,672		$ 14,291	$ 13,238	$ (71)	[1]	$ 7,274		$ (10,431)		$ (970)		$ 75,229	$ (4,198)		$ 36,882
Basic - weighted average common shares (in shares)	17,018	[1]	17,218		17,384	17,357	16,642	[1]	16,538		16,402		16,156		17,245	16,436		16,011
Dilutive effect of common stock equivalents (in shares)															1,006	0	[3]	406
Diluted - weighted average common shares (in shares)	18,026	[1]	18,120		18,192	18,664	16,642	[1],[4]	17,517		16,402	[4]	16,156	[4]	18,251	16,436	[5]	16,417
Earnings (loss) per share [Abstract]
Basic (in dollars per share)	$ 1.71	[1]	$ 1.08		$ 0.82	$ 0.76	$ 0	[1]	$ 0.44		$ (0.64)		$ (0.06)		$ 4.36	$ (0.26)		$ 2.30
Diluted (in dollars per share)	$ 1.61	[1]	$ 1.03		$ 0.79	$ 0.71	$ 0	[1]	$ 0.42		$ (0.64)		$ (0.06)		$ 4.12	$ (0.26)		$ 2.25
Minimum [Member] | Furniture, Fixtures and Equipment [Member]
Property and Equipment [Abstract]
Estimated useful life															3 years
Minimum [Member] | Building and Building Improvements [Member]
Property and Equipment [Abstract]
Estimated useful life															10 years
Maximum [Member] | Furniture, Fixtures and Equipment [Member]
Property and Equipment [Abstract]
Estimated useful life															5 years
Maximum [Member] | Building and Building Improvements [Member]
Property and Equipment [Abstract]
Estimated useful life															40 years
ShipStation [Member]
Principles of Consolidation [Abstract]
Percentage of outstanding equity purchased																						100.00%
Percentage of voting control in Auctane LLC	100.00%														100.00%
Fair Value of Financial Instruments [Abstract]
Contingent consideration charges																$ 1,300
ShipWorks [Member]
Principles of Consolidation [Abstract]
Percentage of outstanding equity purchased																					100.00%
PhotoStamps Inc [Member]
Principles of Consolidation [Abstract]
Percentage of voting control in Auctane LLC	100.00%														100.00%
Endicia [Member]
Principles of Consolidation [Abstract]
Percentage of outstanding equity purchased																				100.00%
ShippingEasy [Member]
Principles of Consolidation [Abstract]
Percentage of outstanding equity purchased																			100.00%
Fair Value of Financial Instruments [Abstract]
Contingent consideration charges															$ 1,900
Stock Options [Member]
Anti-dilutive Shares Excluded from Computation of Diluted Shares [Abstract]
Anti-dilutive stock options (in shares)															211	3,596		134
[1]	The fourth quarter results of 2015 include the impact of the Company's acquisition of Endicia.
[2]	The third and fourth quarter results of 2016 include the impact of the Company's acquisition of ShippingEasy.
[3]	Common stock equivalents are excluded from the diluted net loss per share calculation as their effect is anti-dilutive. The shares related to the 2015 contingent consideration are not included because they are anti-dilutive.
[4]	Common stock equivalents are excluded from the diluted earnings per share calculation as their effect is anti-dilutive.
[5]	Common equivalent shares are excluded from the diluted loss per share as their effect is anti-dilutive.

Summary of Significant Accoun36

Summary of Significant Accounting Policies, Revenue Recognition through Treasury Stock (Details) $ in Thousands	6 Months Ended	12 Months Ended
	Dec. 31, 2016USD ($)Criteria	Dec. 31, 2016USD ($)Criteriashares		Dec. 31, 2015USD ($)Segmentshares		Dec. 31, 2014USD ($)shares
Revenue Recognition [Abstract]
Number of criteria to be met for recognition of revenue | Criteria	4	4
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense		$ 33,949	[1]	$ 17,226	[2]	$ 4,799
Segment Information [Abstract]
Number of operating segments | Segment				2
Number of reporting segments | Segment				1
Short- Term Financing Obligation [Abstract]
Short-term financing obligations	$ 15,554	15,554		$ 13,313
Unused credits	90,000	90,000		34,200
Stock-Based Compensation [Abstract]
Change in the fair value of our contingent consideration liability		$ 0		$ 46,088		$ 8,438
Weighted Average Assumptions Used in Black-Scholes Valuation Model [Abstract]
Expected dividend yield		0.00%		0.00%		0.00%
Risk-free interest rate		0.99%		1.00%		0.87%
Expected volatility		48.00%		46.00%		50.00%
Expected life		3 years 4 months 24 days		3 years 4 months 24 days		3 years 6 months
Expected forfeiture rate		6.00%		6.00%		6.00%
Treasury Stock [Abstract]
Stock repurchased during period, shares (in shares) | shares		844,000		0		435,000
Stock repurchased during period, amount		$ 80,571				$ 12,888
Ship Station [Member]
Stock-Based Compensation [Abstract]
Change in the fair value of our contingent consideration liability				$ 1,300
ShippingEasy [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 1,900
Stock-Based Compensation [Abstract]
Change in the fair value of our contingent consideration liability		1,900
Employee and Director Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense		32,891		16,644		4,473
Employee Stock Purchases [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense		1,058		582		326
Cost of Revenues [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense		1,828		995		402
Sales and Marketing [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense		7,194		4,549		955
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense		6,633		3,149		998
General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense		$ 18,294		$ 8,533		$ 2,444
Maximum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Vesting period		5 years
Maximum [Member] | Endicia [Member]
Segment Information [Abstract]
Concentration risk, percentage						1.00%
Maximum [Member] | Endicia [Member] | Revenue, Net [Member]
Segment Information [Abstract]
Concentration risk, percentage		100.00%		100.00%
[1]	Included in this amount is $1.9 million of stock-based compensation expense relating to performance based equity awards granted in connection with our acquisition of ShippingEasy. See Note - 3 "Acquisitions."
[2]	Included in this amount is $1.3 million of stock-based compensation expense relating to the change in the fair value of our contingent consideration liability in connection with our acquisition of ShipStation. See Note - 3 "Acquisitions."

Acquisition (Details)

Acquisition (Details)

Jul. 02, 2016USD ($)ShoppingCartsEmployeesshares

Nov. 18, 2015USD ($)

Mar. 22, 2015USD ($)

Aug. 29, 2014USD ($)

Jun. 10, 2014USD ($)

Dec. 31, 2016USD ($)

Mar. 31, 2016USD ($)shares

Mar. 31, 2015shares

Dec. 31, 2014USD ($)

Dec. 31, 2016USD ($)shares

Dec. 31, 2014USD ($)shares

Dec. 31, 2016USD ($)$ / shares

Dec. 31, 2015USD ($)$ / sharesshares

Dec. 31, 2014USD ($)$ / shares

Dec. 31, 2013USD ($)$ / shares

Nov. 30, 2015

Business Acquisition [Line Items]

Stock-based compensation expense

$ 33,949,000

[1]

$ 17,226,000

[2]

$ 4,799,000

Purchased Price [Abstract]

Cash consideration

573,000

214,165,000

0

Outstanding debt

$ 148,818,000

$ 148,818,000

148,818,000

Acquisition and integration related expenses

1,100,000

4,400,000

1,100,000

Increase of deferred tax liability and goodwill

173,000

Allocation of Purchase Price [Abstract]

Goodwill

239,705,000

$ 66,893,000

239,705,000

$ 66,893,000

239,705,000

197,807,000

66,893,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Amortization of acquired intangible assets per quarter

14,600,000

3,800,000

1,600,000

Pro-Forma Financial Information [Abstract]

Valuation allowance recognized

$ 0

0

13,554,000

Maximum [Member]

Business Acquisition [Line Items]

Option vesting period

5 years

Term Loan Facility [Member]

Purchased Price [Abstract]

Maximum borrowing capacity

$ 82,500,000

Outstanding debt

76,800,000

76,800,000

$ 76,800,000

Revolving Credit Facility [Member]

Purchased Price [Abstract]

Maximum borrowing capacity

82,500,000

Outstanding debt

72,000,000

72,000,000

72,000,000

Letter of Credit [Member]

Purchased Price [Abstract]

Outstanding debt

$ 510,000

$ 510,000

510,000

ShippingEasy [Member]

Business Acquisition [Line Items]

Percentage of voting interests acquired

100.00%

Number of automatic order importing carts and marketplace | ShoppingCarts

55

Percentage of awards subject to proration

75.00%

Earnings target percentage

100.00%

Stock-based compensation expense

$ 1,900,000

Stock-based compensation expense (in shares) | shares

21,783

Stock-based compensation expense, percentage

100.00%

Purchased Price [Abstract]

Cash consideration

$ 55,000,000

Allocation of Purchase Price [Abstract]

Trade accounts receivable

1,194,000

Other assets

76,000

Property and equipment

40,000

Goodwill

40,953,000

Identifiable intangible assets

15,679,000

Accrued expenses and other liabilities

(707,000)

Deferred revenue

(185,000)

Deferred tax liability

(1,603,000)

Total purchase price

55,447,000

Less: settlement of preexisting relationship (accounts receivable)

1,194,000

Purchase price, net of settlement

$ 54,253,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

5 years

Discount rate of net cash flows to their present values

23.00%

Amortization of acquired intangible assets per quarter

$ 761,000

Pro-Forma Financial Information [Abstract]

Revenues

370,560,000

219,426,000

(Loss) income from operations

121,537,000

(9,138,000)

Net (loss) income

$ 75,810,000

$ (6,608,000)

Basic earnings (loss) per share (in dollars per share) | $ / shares

$ 4.40

$ (0.40)

Diluted earnings (loss) per share (in dollars per share) | $ / shares

$ 4.15

$ (0.40)

[3]

ShippingEasy [Member] | Trade Name [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 1,304,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

8 years

ShippingEasy [Member] | Developed Technology [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 6,948,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

5 years

ShippingEasy [Member] | Customer Relationships [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 6,316,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

5 years

ShippingEasy [Member] | Non-Compete Agreement [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 1,111,000

ShippingEasy [Member] | Non-Compete Agreement [Member] | Minimum [Member]

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

3 years

ShippingEasy [Member] | Non-Compete Agreement [Member] | Maximum [Member]

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

5 years

ShippingEasy [Member] | General Manager and Chief Technology Officer [Member]

Business Acquisition [Line Items]

Aggregate shares issued (in shares) | shares

43,567

Period of performance based inducement equity awards

2 years 6 months

ShippingEasy [Member] | New Employee [Member]

Business Acquisition [Line Items]

Aggregate shares issued (in shares) | shares

62,000

Shares granted for number of new employees | Employees

48

Vesting term

10 years

ShippingEasy [Member] | Vesting Option One [Member] | New Employee [Member]

Business Acquisition [Line Items]

Percentage of options vesting

25.00%

Option vesting period

1 year

ShippingEasy [Member] | Vesting Option Two [Member] | New Employee [Member]

Business Acquisition [Line Items]

Percentage of options vesting

75.00%

Option vesting period

36 months

Endicia [Member]

Business Acquisition [Line Items]

Percentage of voting interests acquired

100.00%

Purchased Price [Abstract]

Cash consideration

214,200,000

$ 215,000,000

Net working capital adjustment

$ 945,000

Debt issuance costs

1,500,000

Debt issuance costs including costs incurred prior to closing

1,800,000

Costs incurred prior to closing

300,000

Maturity date

Nov. 18, 2020

Allocation of Purchase Price [Abstract]

Cash and cash equivalents

5,300,000

Trade accounts receivable

10,247,000

Other assets

771,000

Property and equipment

2,798,000

Goodwill

131,860,000

Identifiable intangible assets

80,200,000

Accrued expenses and other liabilities

(10,212,000)

Deferred revenue

(926,000)

Total purchase price

$ 214,738,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

7 years

Business acquisition purchase price allocation goodwill tax deductible period

15 years

Discount rate of net cash flows to their present values

20.00%

20.00%

20.00%

Amortization of acquired intangible assets per quarter

$ 2,500,000

Fair value of the contingent consideration

221,000,000

Pro-Forma Financial Information [Abstract]

Revenues

$ 273,055,000

204,628,000

(Loss) income from operations

(7,657,000)

20,820,000

Net (loss) income

$ (9,273,000)

$ 32,536,000

[4]

Basic earnings (loss) per share (in dollars per share) | $ / shares

$ (0.58)

$ 2.03

Diluted earnings (loss) per share (in dollars per share) | $ / shares

$ (0.58)

[3]

$ 1.98

Valuation allowance recognized

$ 13,600,000

Endicia [Member] | Trade Name [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 10,900,000

Endicia [Member] | Developed Technology [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 26,100,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

9 years

Endicia [Member] | Customer Relationships [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 43,200,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

6 years

Endicia [Member] | Term Loan Facility [Member]

Purchased Price [Abstract]

Maximum borrowing capacity

82,500,000

Outstanding debt

$ 76,800,000

$ 76,800,000

76,800,000

Endicia [Member] | Revolving Credit Facility [Member]

Purchased Price [Abstract]

Maximum borrowing capacity

82,500,000

Outstanding debt

72,000,000

72,000,000

72,000,000

Available and unused borrowings under the revolving credit facility

10,000,000

10,000,000

10,000,000

Endicia [Member] | Letter of Credit [Member]

Purchased Price [Abstract]

Outstanding debt

$ 510,000

$ 510,000

$ 510,000

Endicia [Member] | Credit Agreement [Member]

Purchased Price [Abstract]

Cash consideration

56,500,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Fair value of the contingent consideration

$ 164,500,000

ShipWorks [Member]

Business Acquisition [Line Items]

Percentage of voting interests acquired

100.00%

Purchased Price [Abstract]

Cash consideration

$ 21,952,000

Contingent consideration or deferred consideration

181,000

Total purchase price

22,133,000

Allocation of Purchase Price [Abstract]

Cash and cash equivalents

803,000

Trade accounts receivable

353,000

Other assets

21,000

Property and equipment

1,091,000

Goodwill

16,349,000

Identifiable intangible assets

4,900,000

Accrued expenses and other liabilities

(1,119,000)

Deferred revenue

(265,000)

Total purchase price

$ 22,133,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

6 years

Business acquisition purchase price allocation goodwill tax deductible period

15 years

Discount rate of net cash flows to their present values

13.00%

13.00%

13.00%

Amortization of acquired intangible assets per quarter

$ 200,000

Adjusted purchase price

$ 69,000

ShipWorks [Member] | Trademark [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 200,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

6 years

ShipWorks [Member] | Developed Technology [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 1,700,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

7 years

ShipWorks [Member] | Customer Relationships [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 2,300,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

6 years

ShipWorks [Member] | Non-Compete Agreement [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 700,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

4 years

ShipStation [Member]

Business Acquisition [Line Items]

Percentage of voting interests acquired

100.00%

Purchased Price [Abstract]

Cash consideration

$ 50,000,000

Contingent consideration or deferred consideration

16,242,000

Total purchase price

66,242,000

Shares available for the earn-out payment period (in shares) | shares

192,225

Shares available during second earn out period (in shares) | shares

576,675

Allocation of Purchase Price [Abstract]

Cash and cash equivalents

1,117,000

Trade accounts receivable

254,000

Other assets

39,000

Property and equipment

187,000

Goodwill

50,544,000

Identifiable intangible assets

15,200,000

Accrued expenses and other liabilities

(835,000)

Deferred revenue

(264,000)

Total purchase price

$ 66,242,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

8 years

Business acquisition purchase price allocation goodwill tax deductible period

15 years

Discount rate of net cash flows to their present values

15.00%

15.00%

15.00%

Amortization of acquired intangible assets per quarter

$ 500,000

Fair value of the contingent consideration

$ 63,200,000

ShipStation [Member] | Minimum [Member]

Purchased Price [Abstract]

Range of acquiree shares available for the performance linked earn-out (in shares) | shares

576,675

576,675

ShipStation [Member] | Maximum [Member]

Purchased Price [Abstract]

Range of acquiree shares available for the performance linked earn-out (in shares) | shares

768,900

768,900

ShipStation [Member] | Trademark [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 500,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

4 years

ShipStation [Member] | Developed Technology [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 5,300,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

8 years

ShipStation [Member] | Customer Relationships [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 9,000,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

8 years

ShipStation [Member] | Non-Compete Agreement [Member]

Allocation of Purchase Price [Abstract]

Identifiable intangible assets

$ 400,000

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Identifiable intangible assets, weighted average estimated useful life

4 years

ShipStation and ShipWorks [Member]

Identifiable Intangible Assets, Weighted Average Estimated Useful Life [Abstract]

Contingent consideration charge

8,800,000

Pro-Forma Financial Information [Abstract]

Revenues

154,459,000

$ 137,626,000

(Loss) income from operations

32,873,000

33,208,000

Net (loss) income

$ 32,342,000

$ 56,691,000

[5]

Basic earnings (loss) per share (in dollars per share) | $ / shares

$ 2.02

$ 3.61

Diluted earnings (loss) per share (in dollars per share) | $ / shares

$ 1.97

$ 3.48

Valuation allowance recognized

$ 13,600,000

$ 9,700,000

[1]

Included in this amount is $1.9 million of stock-based compensation expense relating to performance based equity awards granted in connection with our acquisition of ShippingEasy. See Note - 3 "Acquisitions."

[2]

Included in this amount is $1.3 million of stock-based compensation expense relating to the change in the fair value of our contingent consideration liability in connection with our acquisition of ShipStation. See Note - 3 "Acquisitions."

[3]

Common stock equivalents are excluded from the diluted net loss per share calculation as their effect is anti-dilutive.

[4]

Pro-forma net income of $32.5 million in 2014 includes valuation allowance releases of $13.6 million.

[5]

Pro-forma net income of $56.7 million in 2013 includes valuation allowance releases of $13.6 million and $9.7 million recognized in 2014 and 2013, respectively.

Goodwill and Intangible Asset38

Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 197,807	$ 66,893
Purchase price adjustment (see Note 3 - "Acquisitions")	945
Acquisitions (see Note 3 - "Acquisitions")	40,953	130,914
Goodwill ending balance	239,705	197,807	$ 66,893
Intangible Assets [Abstract]
Amortizable and non-amortizable intangible assets gross carrying amount	125,400	109,700
Non-amortizable assets	11,400
Gross Carrying Amount	113,968	98,289
Accumulated Amortization	28,329	13,728
Total	85,639	84,561
Amortization of intangible assets	$ 14,600	3,800	$ 1,600
Identifiable intangible assets, weighted average remaining useful life	6 years
Amortization Expense, Fiscal Year Maturity [Abstract]
2,017	$ 16,038
2,018	15,854
2,019	15,608
2,020	15,440
2,021	13,040
Thereafter	9,659
Total	85,639	84,561
Patents and Others [Member]
Intangible Assets [Abstract]
Gross Carrying Amount	8,889	8,889
Accumulated Amortization	8,774	8,729
Total	115	160
Amortization Expense, Fiscal Year Maturity [Abstract]
Total	115	160
Customer Relationships [Member]
Intangible Assets [Abstract]
Gross Carrying Amount	60,816	54,500
Accumulated Amortization	12,199	2,773
Total	48,617	51,727
Amortization Expense, Fiscal Year Maturity [Abstract]
Total	48,617	51,727
Technology [Member]
Intangible Assets [Abstract]
Gross Carrying Amount	40,048	33,100
Accumulated Amortization	6,100	1,598
Total	33,948	31,502
Amortization Expense, Fiscal Year Maturity [Abstract]
Total	33,948	31,502
Non-Compete [Member]
Intangible Assets [Abstract]
Gross Carrying Amount	2,211	1,100
Accumulated Amortization	777	389
Total	1,434	711
Amortization Expense, Fiscal Year Maturity [Abstract]
Total	1,434	711
Trademark [Member]
Intangible Assets [Abstract]
Gross Carrying Amount	2,004	700
Accumulated Amortization	479	239
Total	1,525	461
Amortization Expense, Fiscal Year Maturity [Abstract]
Total	$ 1,525	$ 461

Cash, Cash Equivalents and In39

Cash, Cash Equivalents and Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash, Cash Equivalents and Investments [Abstract]
Unrealized losses on security held	$ 0	$ 0	$ 0
Other than temporary impairment	0	0	0
Cash and cash equivalents [Abstract]
Cost or Amortized Cost	106,932	65,126	$ 40,933	$ 66,674
Contractual maturities of marketable fixed-income securities [Abstract]
Due within one year, Amortized Cost	1,500
Due after one year, amortized cost	0
Total, Amortized Cost	1,500
Due within one year, Estimated Fair Value	1,511
Due after one year, fair value	0
Total, Estimated Fair Value	1,511
Cash and Cash Equivalents [Member]
Cash and cash equivalents [Abstract]
Cost or Amortized Cost	106,932	65,126
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	106,932	65,126
Total Short-Term Investments [Member]
Cash and cash equivalents [Abstract]
Cost or Amortized Cost	1,500	8,549
Gross Unrealized Gains	13	7
Gross Unrealized Losses	(2)	(3)
Estimated Fair Value	1,511	8,553
Long-Term Investments [Member]
Cash and cash equivalents [Abstract]
Cost or Amortized Cost	0	1,515
Gross Unrealized Gains	0	17
Gross Unrealized Losses	0	(3)
Estimated Fair Value	0	1,529
Cash, Cash Equivalents and Investments [Member]
Cash and cash equivalents [Abstract]
Cost or Amortized Cost	108,432	75,190
Gross Unrealized Gains	13	24
Gross Unrealized Losses	(2)	(6)
Estimated Fair Value	108,443	75,208
Cash [Member] | Cash and Cash Equivalents [Member]
Cash and cash equivalents [Abstract]
Cost or Amortized Cost	101,987	63,593
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	101,987	63,593
Money Market [Member] | Cash and Cash Equivalents [Member]
Cash and cash equivalents [Abstract]
Cost or Amortized Cost	4,945	1,533
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	4,945	1,533
Corporate Bonds and Asset Backed Securities [Member] | Total Short-Term Investments [Member]
Cash and cash equivalents [Abstract]
Cost or Amortized Cost	1,500	8,549
Gross Unrealized Gains	13	7
Gross Unrealized Losses	(2)	(3)
Estimated Fair Value	1,511	8,553
Corporate Bonds and Asset Backed Securities [Member] | Long-Term Investments [Member]
Cash and cash equivalents [Abstract]
Cost or Amortized Cost	0	1,515
Gross Unrealized Gains	0	17
Gross Unrealized Losses	0	(3)
Estimated Fair Value	$ 0	$ 1,529

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financial assets measured at fair value on a recurring basis [Abstract]
Available-for-sale debt securities			$ 1,511
Contingent consideration measured at fair value on a recurring basis [Abstract]
Contingent consideration - current			0	$ 63,209
Summary of reconciliation of contingent consideration obligation [Roll Forward]
Contingent consideration			0	46,088	$ 8,438
Recurring [Member]
Financial assets measured at fair value on a recurring basis [Abstract]
Cash and cash equivalents			106,932	65,126
Available-for-sale debt securities			1,511	10,082
Total			108,443	75,208
Contingent consideration measured at fair value on a recurring basis [Abstract]
Contingent consideration - current				63,209
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets measured at fair value on a recurring basis [Abstract]
Cash and cash equivalents			106,932	65,126
Available-for-sale debt securities			0	0
Total			106,932	65,126
Contingent consideration measured at fair value on a recurring basis [Abstract]
Contingent consideration - current				63,209
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets measured at fair value on a recurring basis [Abstract]
Cash and cash equivalents			0	0
Available-for-sale debt securities			1,511	10,082
Total			1,511	10,082
Contingent consideration measured at fair value on a recurring basis [Abstract]
Contingent consideration - current				0
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Financial assets measured at fair value on a recurring basis [Abstract]
Cash and cash equivalents			0	0
Available-for-sale debt securities			0	0
Total			0	0
Contingent consideration measured at fair value on a recurring basis [Abstract]
Contingent consideration - current				0
Summary of reconciliation of contingent consideration obligation [Roll Forward]
Contingent consideration, beginning of year balance		$ 63,209	63,209	25,015
Contingent consideration distribution		$ 63,209		(9,225)
Contingent consideration	[1]			46,088
Contingent consideration compensation expense	[1]			1,331
Contingent consideration, end of year balance			$ 0	$ 63,209	$ 25,015
[1]	) This amount represents fair value adjustment during the year to contingent consideration recorded associated with the acquisition of ShipStation. The $46.1 million contingent consideration charge is recorded as a separate line item in our consolidated statement of income. The $1.3 million contingent consideration charge relating to certain employees is recorded in general and administrative expense in operating expense. See Note 3 - "Acquisitions" for further description. At December 31, 2015, the contingent consideration obligation was transferred from level 3 to level 1.

Debt (Details)

Debt (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Nov. 18, 2015
Line of Credit Facility [Line Items]
Amortization of debt issuance expenses	$ 373	$ 31
Outstanding debt	$ 148,818
Interest rate on outstanding loan	2.13%
Unused borrowing capacity	$ 10,000
Consolidated leverage ratio	0.86
Fixed charge coverage ratio	22.11
Total liquidity capital	$ 117,000
Maturities of Long-term Debt [Abstract]
2,017	6,703
2,018	8,766
2,019	10,828
2,020	122,521
2,021	0
Total debt	148,818
Less: debt issuance costs	1,465		$ 1,800
Total debt, net of debt issuance costs	$ 147,353
Minimum [Member]
Line of Credit Facility [Line Items]
Fixed charge coverage ratio	1.25
Total liquidity capital	$ 20,000
Maximum [Member]
Line of Credit Facility [Line Items]
Consolidated leverage ratio	2.75
London Interbank Offered Rate [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.25%
London Interbank Offered Rate [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.25%
London Interbank Offered Rate [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate	2.00%
Term Loan [Member]
Line of Credit Facility [Line Items]
Credit facility maximum borrowing			82,500
Outstanding debt	$ 76,800
Maturities of Long-term Debt [Abstract]
Total debt	76,800
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility maximum borrowing			$ 82,500
Outstanding debt	72,000
Maturities of Long-term Debt [Abstract]
Total debt	72,000
Letter of Credit [Member]
Line of Credit Facility [Line Items]
Outstanding debt	510
Maturities of Long-term Debt [Abstract]
Total debt	$ 510

Accounts Payable and Accrued 42

Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accounts Payable and Accrued Expenses [Abstract]
Payroll and related accrual	$ 15,168	$ 12,863
Cost of revenue, inventory and materials accrual	977	539
Construction and facility expense accrual	1,899	649
Professional fees accrual	3,802	1,973
Sales and marketing related accrual	6,001	5,145
Operating expenses related accrual	35,285	15,613
Short-term financing obligations	15,554	13,313
Other accruals	7,519	10,721
Accounts payable and accrued expenses	$ 86,205	$ 60,816

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 56,999	$ 48,081
Less accumulated depreciation and amortization	(20,170)	(16,374)
Property and equipment, net	36,829	31,707
Depreciation expense	4,600	3,900	$ 3,200
Land [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	7,156	7,156
Building [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	4,886	4,886
Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	17,705	14,048
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,003	1,055
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,509	2,016
Computers and Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 22,740	$ 18,920

Income Taxes (Details)

Income Taxes (Details)	12 Months Ended
	Dec. 31, 2016USD ($)Shareholder	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Income Taxes [Abstract]
Income tax benefit consisting of federal and state alternative minimum taxes	$ 41,700,000	$ 1,400,000
Research and development tax credit carryforwards	10,300,000
Unrecognized tax benefit that would impact effective tax rate	6,200,000	6,000,000	$ 5,200,000
Decrease in unrecognized tax benefits	2,600,000
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Balance	(6,034,000)	(5,223,000)	(2,314,000)
Reduction for tax positions of prior years	2,596,000
Additions for tax positions of prior years	(810,000)	(251,000)	(2,349,000)
Addition for tax position of the current year	(2,156,000)	(560,000)	(560,000)
Settlement	251,000	0	0
Balance	(6,153,000)	(6,034,000)	(5,223,000)
Interest and penalty expense	0	0	0
Deferred tax assets [Abstract]
Net operating loss carryforward	3,406,000	22,024,000
Tax credit carryforwards	16,091,000	6,872,000
Definite lived intangibles	200,000	2,946,000
Contingent consideration	20,461,000	20,742,000
Stock compensation	12,162,000	4,800,000
Accruals	7,771,000	3,534,000
Deferred tax assets	60,091,000	60,918,000
Deferred tax liabilities [Abstract]
Fixed assets	(726,000)	(464,000)
Indefinite lived intangibles	(7,770,000)	(1,922,000)
Federal benefit of state tax deferred tax assets	(2,813,000)	(1,308,000)
Deferred tax liabilities	(11,309,000)	(3,694,000)
Net deferred tax assets	48,782,000	57,224,000
Tax Credit Carryforward [Line Items]
NOL carryforward for federal income tax purpose	15,700,000
NOL carryforward for state income tax purpose	0
NOL carryforwards attributable to employee stock option exercises	6,000,000
Increase in additional paid in capital due to excess tax benefits realized	$ 6,000,000
Percentage ownership required to trigger impairment of NOLs	50.00%
Number of five percent shareholders to trigger change in ownership, minimum | Shareholder	1
Percentage of shares held by single shareholder to trigger change in ownership	5.00%
Period to trigger change in ownership, maximum	3 years
Deferred tax assets associated with federal and state research credits	$ 6,000,000
Current [Abstract]
Federal	2,400,000	806,000	730,000
State	5,722,000	611,000	127,000
Total	8,122,000	1,417,000	857,000
Deferred [Abstract]
Federal	11,023,000	(596,000)	(14,286,000)
State	(3,403,000)	(1,341,000)	652,000
Adjustment for change in tax rate	(781,000)	(1,471,000)	80,000
APIC charge on excess tax benefits	26,784,000	618,000	0
Total	33,623,000	(2,790,000)	(13,554,000)
Income tax expense (benefit)	41,745,000	(1,373,000)	(12,697,000)
Differences Between Provision for Income Taxes and Income Taxes at Statutory Federal Income Tax Rate [Abstract]
Income tax at statutory federal rate	40,941,000	(1,950,000)	8,223,000
State tax - net of federal benefit	4,127,000	(2,000)	290,000
Stock-based compensation	2,757,000	851,000	497,000
Nondeductible items	485,000	902,000	15,000
Research and development	(1,963,000)	0	0
Uncertain tax positions	(2,048,000)	173,000	1,767,000
Change in tax rate	(781,000)	(1,471,000)	80,000
Change in valuation allowance	0	0	(13,554,000)
Other changes in valuation allowance, net	0	0	(11,480,000)
Other, net	(1,773,000)	124,000	1,465,000
Income tax expense (benefit)	41,745,000	$ (1,373,000)	$ (12,697,000)
ShippingEasy [Member]
Tax Credit Carryforward [Line Items]
NOL carryforward for federal income tax purpose	12,000,000
Federal [Member]
Tax Credit Carryforward [Line Items]
Tax credit carryforward	11,400,000
State [Member]
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 4,700,000

Employee Stock Plans (Details)

Employee Stock Plans (Details) $ / shares in Units, $ in Thousands	Jul. 02, 2016EmployeesPlanshares	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)$ / sharesshares
Options Outstanding, Number of Options [Roll Forward]
Balance (in shares) | shares		3,106,000	2,969,000	996,000
Granted (in shares) | shares		816,000	694,000	2,251,000
Forfeited (in shares) | shares		(198,000)	(98,000)	(75,000)
Exercised (in shares) | shares		(432,000)	(459,000)	(203,000)
Forfeited or expired (in shares) | shares		(198,000)
Balance (in shares) | shares		3,292,000	3,106,000	2,969,000
Exercisable (in shares) | shares		1,711,000
Weighted Average Exercise Price per Share [Roll Forward]
Balance (in dollars per share)		$ 37.75	$ 28.91	$ 18.12
Granted (in dollars per share)		91.36	65.96	32.55
Exercised (in dollars per share)		30.04	23.73	16.34
Forfeited (in dollars per share)		72.72	37.43	35.96
Forfeited or expired (in dollars per share)		72.72
Balance (in dollars per share)		49.95	37.75	28.91
Exercisable (in dollars per share)		$ 35.14
Weighted Average Remaining Contractual Life [Abstract]
Balance at December 31, 2014		7 years 10 months 24 days
Exercisable at December 31, 2014		7 years 2 months 12 days
Aggregate Intrinsic Value [Abstract]
Balance at December, 31, 2014 | $		$ 213,066
Exercisable at December, 31, 2014 | $		$ 136,056
Weighted-Average Fair Value of Stock Grants Using Black-Scholes Valuation Model [Abstract]
Weighted-average fair value of stock options with an exercise price equal to the market price on the grant date (in dollars per share)		$ 32.27	23.19	11.87
Weighted-average fair value of stock options with an exercise price greater than the market price on the grant date (in dollars per share)		0	0	0
Total (in dollars per share)		32.27	23.19	11.87
Weighted Average Exercise Prices for Stock Options Exercised [Abstract]
Weighted-average exercise price of stock options with an exercise price equal to the market price on the grant date (in dollars per share)		30.04
Weighted-average exercise price of stock options with an exercise price greater than the market price on the grant date (in dollars per share)		0
Total weighted-average exercise price (in dollars per share)		30.04	23.73	16.34
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Closing stock price (in dollars per share)		114.65
Weighted average grant date fair value of options vested (in dollars per share)		$ 30.68	$ 12.46	$ 8.44
Total intrinsic value of options exercised | $		$ 36,500	$ 39,400	$ 6,400
Non-vested Number of Stock Options [Roll Forward]
Nonvested, Beginning Balance (in shares) | shares		1,900,000
Granted (in shares) | shares		816,000
Vested (in shares) | shares		(1,092,000)
Forfeited / Cancelled (in shares) | shares		(42,000)
Nonvested, Ending Balance (in shares) | shares		1,582,000	1,900,000
Weighted Average Grant Date Fair Value per Option [Roll Forward]
Nonvested, Beginning Balance (in dollars per share)		$ 29.62
Granted (in dollars per share)		32.37
Vested (in dollars per share)		30.68
Forfeited / Cancelled (in dollars per share)		21.65
Nonvested, Ending Balance (in dollars per share)		$ 30.35	$ 29.62
Total unrecognized compensation cost related to non-vested share-based compensation arrangements | $		$ 44,500
Weighted-average period for recognition of unrecognized non-vested share-based compensation		2 years
ShippingEasy [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of awards subject to proration	75.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option vesting period		5 years
Stock Incentive Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of common shares reserved for future issuance upon adoption (in shares) | shares		3,500,000
Maximum aggregate number of shares of common stock and stock equivalents (in shares) | shares		2,100,000
Stock available for future issuance (in shares) | shares		3,500,000
Stock Incentive Plans [Member] | Board of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of common shares reserved for future issuance upon adoption (in shares) | shares		1,370,000
Maximum aggregate number of shares of common stock and stock equivalents (in shares) | shares		1,200,000
Stock available for future issuance (in shares) | shares		1,370,000
Stock Incentive Plans [Member] | Restricted Stock and Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Full value awards counted against Plan's overall limits (in shares) | shares		2
Earlier Full value awards counted against Plan's overall limits (in shares) | shares		1
Stock Incentive Plans [Member] | Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Full value awards counted against Plan's overall limits (in shares) | shares		1
Stock Incentive Plans [Member] | Performance-based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate shares issued (in shares) | shares		175,000
Option vesting period		36 months
Compensation expense | $		$ 1,300	$ 646
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contribution by participants of cash earnings through payroll deductions, maximum		15.00%
Purchase price per share of fair market value on participant's entry date into offering period		85.00%
Aggregate number of common shares reserved for future issuance upon adoption (in shares) | shares		150,000
Stock available for future issuance (in shares) | shares		150,000
Increase in percentage of total number of outstanding shares of our common stock		1.00%
Extension of period beyond expiration date		10 years
Shares held in ESPP (in shares) | shares		1,600,000	1,600,000
Aggregate shares issued (in shares) | shares		35,000	49,000	42,000
Employee Stock Purchase Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock were reserved for annual issuance, maximum (in shares) | shares		260,786
Savings Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense | $		$ 1,100	$ 650	$ 402
Equity Inducement Plan [Member] | ShippingEasy [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of performance based inducement equity awards	2 years 6 months
Percentage of awards subject to proration	75.00%
Shares granted for number of new employees | Employees	48
Vesting term	10 years
Number of inducement plans | Plan	2
Equity Inducement Plan [Member] | ShippingEasy [Member] | Vesting Option One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option vesting period	1 year
Percentage of options vesting	25.00%
Equity Inducement Plan [Member] | ShippingEasy [Member] | Vesting Option Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option vesting period	36 months
Percentage of options vesting	75.00%
Equity Inducement Plan [Member] | Performance-based Awards [Member] | ShippingEasy [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate shares issued (in shares) | shares	62,000
Equity Inducement Plan [Member] | Performance-based Awards [Member] | Maximum [Member] | Executives [Member] | ShippingEasy [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate shares issued (in shares) | shares	87,000
$0.00 - $9.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower (in dollars per share)		$ 0
Range of Exercise Prices, upper (in dollars per share)		$ 9.99
Options Outstanding, Number Outstanding (in shares) | shares		18,000
Options Outstanding, Weighted Average Remaining Contractual Life		2 years 3 months 18 days
Options Outstanding, Weighted Average Exercise Price per Share (in dollars per share)		$ 9.12
Options Exercisable, Number Exercisable (in shares) | shares		18,000
Options Exercisable, Weighted Average Exercise Price per Share (in dollars per share)		$ 9.12
$10.00 - $19.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower (in dollars per share)		10
Range of Exercise Prices, upper (in dollars per share)		$ 19.99
Options Outstanding, Number Outstanding (in shares) | shares		197,000
Options Outstanding, Weighted Average Remaining Contractual Life		4 years
Options Outstanding, Weighted Average Exercise Price per Share (in dollars per share)		$ 12.62
Options Exercisable, Number Exercisable (in shares) | shares		197,000
Options Exercisable, Weighted Average Exercise Price per Share (in dollars per share)		$ 12.62
$20.00 - $29.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower (in dollars per share)		20
Range of Exercise Prices, upper (in dollars per share)		$ 29.99
Options Outstanding, Number Outstanding (in shares) | shares		89,000
Options Outstanding, Weighted Average Remaining Contractual Life		6 years
Options Outstanding, Weighted Average Exercise Price per Share (in dollars per share)		$ 26.17
Options Exercisable, Number Exercisable (in shares) | shares		79,000
Options Exercisable, Weighted Average Exercise Price per Share (in dollars per share)		$ 25.83
$30.00 - $39.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower (in dollars per share)		30
Range of Exercise Prices, upper (in dollars per share)		$ 39.99
Options Outstanding, Number Outstanding (in shares) | shares		1,649,000
Options Outstanding, Weighted Average Remaining Contractual Life		7 years 8 months 12 days
Options Outstanding, Weighted Average Exercise Price per Share (in dollars per share)		$ 32.57
Options Exercisable, Number Exercisable (in shares) | shares		1,132,000
Options Exercisable, Weighted Average Exercise Price per Share (in dollars per share)		$ 32.59
$40.00 - $49.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower (in dollars per share)		40
Range of Exercise Prices, upper (in dollars per share)		$ 49.99
Options Outstanding, Number Outstanding (in shares) | shares		72,000
Options Outstanding, Weighted Average Remaining Contractual Life		7 years 7 months 6 days
Options Outstanding, Weighted Average Exercise Price per Share (in dollars per share)		$ 45.23
Options Exercisable, Number Exercisable (in shares) | shares		43,000
Options Exercisable, Weighted Average Exercise Price per Share (in dollars per share)		$ 45.06
$50.00 - $59.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower (in dollars per share)		50
Range of Exercise Prices, upper (in dollars per share)		$ 59.99
Options Outstanding, Number Outstanding (in shares) | shares		122,000
Options Outstanding, Weighted Average Remaining Contractual Life		8 years 2 months 12 days
Options Outstanding, Weighted Average Exercise Price per Share (in dollars per share)		$ 58.25
Options Exercisable, Number Exercisable (in shares) | shares		68,000
Options Exercisable, Weighted Average Exercise Price per Share (in dollars per share)		$ 58.25
$60.00 - $69.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower (in dollars per share)		60
Range of Exercise Prices, upper (in dollars per share)		$ 69.99
Options Outstanding, Number Outstanding (in shares) | shares		216,000
Options Outstanding, Weighted Average Remaining Contractual Life		8 years 3 months 18 days
Options Outstanding, Weighted Average Exercise Price per Share (in dollars per share)		$ 66
Options Exercisable, Number Exercisable (in shares) | shares		77,000
Options Exercisable, Weighted Average Exercise Price per Share (in dollars per share)		$ 66.12
$70.00 - $79.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower (in dollars per share)		70
Range of Exercise Prices, upper (in dollars per share)		$ 79.99
Options Outstanding, Number Outstanding (in shares) | shares		256,000
Options Outstanding, Weighted Average Remaining Contractual Life		8 years 9 months 18 days
Options Outstanding, Weighted Average Exercise Price per Share (in dollars per share)		$ 73.73
Options Exercisable, Number Exercisable (in shares) | shares		72,000
Options Exercisable, Weighted Average Exercise Price per Share (in dollars per share)		$ 72.25
$80.00 - $89.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower (in dollars per share)		80
Range of Exercise Prices, upper (in dollars per share)		$ 89.99
Options Outstanding, Number Outstanding (in shares) | shares		266,000
Options Outstanding, Weighted Average Remaining Contractual Life		9 years 2 months 12 days
Options Outstanding, Weighted Average Exercise Price per Share (in dollars per share)		$ 87.24
Options Exercisable, Number Exercisable (in shares) | shares		0
Options Exercisable, Weighted Average Exercise Price per Share (in dollars per share)		$ 0
$90.00 - $99.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower (in dollars per share)		90
Range of Exercise Prices, upper (in dollars per share)		$ 99.99
Options Outstanding, Number Outstanding (in shares) | shares		361,000
Options Outstanding, Weighted Average Remaining Contractual Life		9 years 4 months 24 days
Options Outstanding, Weighted Average Exercise Price per Share (in dollars per share)		$ 94.51
Options Exercisable, Number Exercisable (in shares) | shares		22,000
Options Exercisable, Weighted Average Exercise Price per Share (in dollars per share)		$ 91.86
$100.00 - $109.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower (in dollars per share)		100
Range of Exercise Prices, upper (in dollars per share)		$ 109.99
Options Outstanding, Number Outstanding (in shares) | shares		42,000
Options Outstanding, Weighted Average Remaining Contractual Life		9 years 7 months 6 days
Options Outstanding, Weighted Average Exercise Price per Share (in dollars per share)		$ 104.11
Options Exercisable, Number Exercisable (in shares) | shares		3,000
Options Exercisable, Weighted Average Exercise Price per Share (in dollars per share)		$ 101.32
$120.00 - $129.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower (in dollars per share)		120
Range of Exercise Prices, upper (in dollars per share)		$ 129.99
Options Outstanding, Number Outstanding (in shares) | shares		5,000
Options Outstanding, Weighted Average Remaining Contractual Life		9 years 2 months 12 days
Options Outstanding, Weighted Average Exercise Price per Share (in dollars per share)		$ 122.25
Options Exercisable, Number Exercisable (in shares) | shares		0
Options Exercisable, Weighted Average Exercise Price per Share (in dollars per share)		$ 0
$0.00 - $129.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower (in dollars per share)		0
Range of Exercise Prices, upper (in dollars per share)		$ 129.99
Options Outstanding, Number Outstanding (in shares) | shares		3,293,000
Options Outstanding, Weighted Average Remaining Contractual Life		7 years 10 months 24 days
Options Outstanding, Weighted Average Exercise Price per Share (in dollars per share)		$ 49.95
Options Exercisable, Number Exercisable (in shares) | shares		1,711,000
Options Exercisable, Weighted Average Exercise Price per Share (in dollars per share)		$ 35.14

Commitments and Contingencies46

Commitments and Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments and Contingencies [Abstract]
Rent expense	$ 3,000	$ 874	$ 215
Future Minimum Lease Payment Under Operating Leases [Abstract]
2,017	4,048
2,018	3,563
2,019	1,369
2,020	1,396
2,021	1,052
Thereafter	0
Total	$ 11,428

Quarterly Information (Unaudi47

Quarterly Information (Unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended														12 Months Ended
	Dec. 31, 2016	[1]	Sep. 30, 2016	[2]	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	[1]	Sep. 30, 2015	[2]	Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Quarterly Information (Unaudited) [Abstract]
Revenues	$ 105,896		$ 92,559		$ 84,013	$ 81,837	$ 69,876		$ 51,669		$ 48,360		$ 44,052		$ 364,305	$ 213,957		$ 147,269
Gross profit	87,993		75,832		70,293	67,215	56,693		40,480		38,422		34,427		301,333	170,022		114,363
Income (loss) from operations	41,443		31,591		24,967	22,219	(1,000)		12,991		(15,152)		(2,159)		120,220	(5,320)		23,810
Net income (loss)	$ 29,028		$ 18,672		$ 14,291	$ 13,238	$ (71)		$ 7,274		$ (10,431)		$ (970)		$ 75,229	$ (4,198)		$ 36,882
Net (loss) income per share [Abstract]
Basic (in dollars per share)	$ 1.71		$ 1.08		$ 0.82	$ 0.76	$ 0		$ 0.44		$ (0.64)		$ (0.06)		$ 4.36	$ (0.26)		$ 2.30
Diluted (in dollars per share)	$ 1.61		$ 1.03		$ 0.79	$ 0.71	$ 0		$ 0.42		$ (0.64)		$ (0.06)		$ 4.12	$ (0.26)		$ 2.25
Weighted average shares outstanding [Abstract]
Basic (in shares)	17,018		17,218		17,384	17,357	16,642		16,538		16,402		16,156		17,245	16,436		16,011
Diluted (in shares)	18,026		18,120		18,192	18,664	16,642	[3]	17,517		16,402	[3]	16,156	[3]	18,251	16,436	[4]	16,417
[1]	The fourth quarter results of 2015 include the impact of the Company's acquisition of Endicia.
[2]	The third and fourth quarter results of 2016 include the impact of the Company's acquisition of ShippingEasy.
[3]	Common stock equivalents are excluded from the diluted earnings per share calculation as their effect is anti-dilutive.
[4]	Common equivalent shares are excluded from the diluted loss per share as their effect is anti-dilutive.