SPS Commerce (SPSC) 10-Q 26 Oct 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 19, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	SPSC
Entity Registrant Name	SPS COMMERCE INC
Entity Central Index Key	1,092,699
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		17,664,624

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
CURRENT ASSETS
Cash and cash equivalents	$ 144,748	$ 123,127
Short-term investments	44,654	40,192
Accounts receivable, less allowance for doubtful accounts of $1,199 and $763, respectively	27,289	24,897
Deferred costs	33,134	29,966
Other current assets	6,613	6,149
Total current assets	256,438	224,331
PROPERTY AND EQUIPMENT, net	19,368	16,856
GOODWILL	50,502	51,613
INTANGIBLE ASSETS, net	13,491	16,529
INVESTMENTS	4,921	5,206
OTHER ASSETS
Deferred costs	10,597	9,967
Deferred income tax asset	11,433	13,697
Other assets	1,710	1,539
Total assets	368,460	339,738
CURRENT LIABILITIES
Accounts payable	3,853	4,463
Accrued compensation	15,498	15,228
Accrued expenses	3,976	4,712
Deferred revenue	24,948	17,863
Deferred rent	1,399	1,679
Total current liabilities	49,674	43,945
OTHER LIABILITIES
Deferred revenue	2,685	2,731
Deferred rent	3,979	3,064
Deferred income tax liability	1,551	1,887
Total liabilities	57,889	51,627
COMMITMENTS and CONTINGENCIES
STOCKHOLDERS’ EQUITY
Preferred stock, $0.001 par value; 5,000,000 shares authorized; 0 shares issued and outstanding
Common stock, $0.001 par value; 55,000,000 shares authorized; 17,644,364 and 17,249,153 shares issued; and 17,302,572 and 17,127,006 outstanding, respectively	18	17
Treasury stock, at cost; 341,792 and 122,147 shares, respectively	(19,682)	(5,815)
Additional paid-in capital	323,539	301,863
Retained earnings (accumulated deficit)	8,120	(8,611)
Accumulated other comprehensive (loss) income	(1,424)	657
Total stockholders’ equity	310,571	288,111
Total liabilities and stockholders’ equity	$ 368,460	$ 339,738

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,199	$ 763
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	55,000,000	55,000,000
Common stock, shares issued	17,644,364	17,249,153
Common stock, shares outstanding	17,302,572	17,127,006
Treasury stock, shares	341,792	122,147

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenues	$ 62,868	$ 56,057	$ 183,051	$ 162,028
Cost of revenues	20,411	18,645	60,571	54,166
Gross profit	42,457	37,412	122,480	107,862
Operating expenses
Sales and marketing	16,952	17,638	54,023	52,981
Research and development	5,146	6,549	15,571	17,023
General and administrative	11,174	8,743	31,278	24,709
Amortization of intangible assets	928	1,128	3,086	3,460
Total operating expenses	34,200	34,058	103,958	98,173
Income from operations	8,257	3,354	18,522	9,689
Other income (expense)
Interest income, net	628	272	1,589	704
Other expense, net	(219)	(195)	(541)	(356)
Total other income, net	409	77	1,048	348
Income before income taxes	8,666	3,431	19,570	10,037
Income tax expense	605	1,255	2,839	2,908
Net income	$ 8,061	$ 2,176	$ 16,731	$ 7,129
Net income per share
Basic	$ 0.47	$ 0.13	$ 0.97	$ 0.42
Diluted	$ 0.45	$ 0.13	$ 0.95	$ 0.41
Weighted average common shares used to compute net income per share
Basic	17,219	17,223	17,167	17,192
Diluted	17,741	17,410	17,557	17,394
Other comprehensive income
Foreign currency translation adjustments	$ 76	$ 1,779	$ (2,155)	$ 4,291
Unrealized gain on investments, net of tax of $41, $10, $88 and $0	123	17	264
Reclassification of unrealized (gain) loss on investments into earnings, net of tax of ($11), $44, ($64) and $29	(33)	72	(191)	48
Comprehensive income	$ 8,227	$ 4,044	$ 14,649	$ 11,468

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Unrealized gain on investment, tax	$ 41	$ 10	$ 88	$ 0
Reclassification of unrealized (gain) loss on investments into earnings, tax	$ (11)	$ 44	$ (64)	$ 29

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net income	$ 16,731	$ 7,129
Reconciliation of net income to net cash provided by operating activities
Deferred income taxes	1,934	2,240
Depreciation and amortization of property and equipment	6,308	5,261
Amortization of intangible assets	3,086	3,460
Provision for doubtful accounts	1,780	1,365
Stock-based compensation	9,978	6,833
Other, net	(255)	(19)
Changes in assets and liabilities
Accounts receivable	(4,279)	(4,476)
Deferred costs	(3,813)	(5,188)
Other current and non-current assets	(681)	1,135
Accounts payable	382	632
Accrued compensation	(592)	(1,517)
Accrued expenses	(718)	469
Deferred revenue	7,039	5,270
Deferred rent	647	(622)
Net cash provided by operating activities	37,547	21,972
Cash flows from investing activities
Purchases of property and equipment	(9,875)	(5,242)
Purchases of investments	(64,434)	(29,819)
Maturities of investments	60,000	23,029
Acquisitions of businesses and intangible assets, net of cash acquired	(381)	(500)
Net cash used in investing activities	(14,690)	(12,532)
Cash flows from financing activities
Repurchases of common stock	(13,867)
Net proceeds from exercise of options to purchase common stock	11,800	1,307
Net proceeds from employee stock purchase plan	836	1,011
Net cash (used in) provided by financing activities	(1,231)	2,318
Effect of foreign currency exchange rate changes	(5)	1,349
Net increase in cash and cash equivalents	21,621	13,107
Cash and cash equivalents at beginning of period	123,127	115,877
Cash and cash equivalents at end of period	$ 144,748	$ 128,984

General

General	9 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
General	NOTE A – General Business Description We are a leading provider of cloud-based supply chain management solutions, providing network-proven fulfillment, sourcing, and item assortment management solutions, along with comprehensive retail performance analytics to thousands of customers worldwide. We provide our solutions through the SPS Commerce Platform, a cloud-based product suite that improves the way retailers, suppliers, distributors and logistics firms orchestrate the sourcing, set up of new vendors and items and fulfillment of products that consumers buy. We derive the majority of our revenues from thousands of monthly recurring subscriptions from businesses that utilize our solutions. Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of SPS Commerce, Inc. and its subsidiaries. All intercompany accounts and transactions have been eliminated in the unaudited condensed consolidated financial statements, which Effective January 1, 2018, we adopted the requirements of Accounting Standards Update ("ASU") No. 2014-09 (“ASU 2014-09”), Revenue from Contracts with Customers (Topic 606) Use of Estimates Preparing financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates. Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU 2014-09 which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This guidance replaced most existing revenue recognition guidance in GAAP. Topic 606 also includes Subtopic 340-40, Other Assets and Deferred Costs – Contracts with Customers We adopted the new standard effective January 1, 2018, on a retrospective basis. The new standard did not impact our recognition of the recurring revenue received from customers for our cloud-based supply chain solutions; however, the adoption of the new standard impacted our accounting for certain upfront set-up fees, the periods over which the related revenues are recognized and the timing of revenue recognition for these set-up fees. The adoption of the new standard also impacted our accounting for certain costs to obtain our contracts, specifically related to the periods over which commissions are recognized as well as the timing of cost recognition. Selected condensed consolidated balance sheet line items, which reflect the adoption of ASU 2014-09 are as follows (in thousands): December 31, 2017 As previously reported Adjustments As adjusted ASSETS Deferred costs $ 25,091 $ 4,875 $ 29,966 Deferred costs, non-current 6,770 3,197 9,967 Deferred income tax asset 17,551 (3,854 ) 13,697 LIABILITIES Accrued compensation 15,886 (658 ) 15,228 Deferred revenue 16,407 1,456 17,863 Deferred revenue, non-current 10,602 (7,871 ) 2,731 STOCKHOLDERS’ EQUITY Accumulated deficit (19,902 ) 11,291 (8,611 ) Selected unaudited condensed consolidated statement of operations line items, which reflect the adoption of ASU 2014-09 are as follows (in thousands): For the three months ended September 30, 2017 As previously reported Adjustments As adjusted Revenues 56,150 (93 ) 56,057 Operating expenses Sales and marketing 18,239 (601 ) 17,638 Income from operations 2,846 508 3,354 Income tax expense 1,058 197 1,255 Net income $ 1,865 $ 311 $ 2,176 Net income per share Basic $ 0.11 $ 0.02 $ 0.13 Diluted $ 0.11 $ 0.02 $ 0.13 For the nine months ended September 30, 2017 As previously reported Adjustments As adjusted Revenues 162,366 (338 ) 162,028 Operating expenses Sales and marketing 54,059 (1,078 ) 52,981 Income from operations 8,949 740 9,689 Income tax expense 2,636 272 2,908 Net income $ 6,661 $ 468 $ 7,129 Net income per share Basic $ 0.39 $ 0.03 $ 0.42 Diluted $ 0.38 $ 0.03 $ 0.41 Selected unaudited condensed consolidated statement of cash flows line items, which reflect the adoption of ASU 2014-09 are as follows (in thousands): For the nine months ended September 30, 2017 As previously reported Adjustments As adjusted Cash flows from operating activities Net income $ 6,661 $ 468 $ 7,129 Reconciliation of net income to net cash provided by operating activities Deferred income taxes 1,968 272 2,240 Changes in assets and liabilities Deferred costs (4,487 ) (701 ) (5,188 ) Accrued compensation (1,140 ) (377 ) (1,517 ) Deferred revenue 4,932 338 5,270 Net cash provided by operating activities 21,972 — 21,972 In March 2018, we adopted FASB ASU 2018-05, Income Taxes (Topic 740): Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118 Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU 2016-02, Leases We will adopt the new standard on January 1, 2019 and use the effective date as our date of initial application. Consequently, financial information will not be updated and the disclosures required under the new standard will not be provided for dates and periods before January 1, 2019. The new standard provides several optional practical expedients in transition. We expect to elect the ‘package of practical expedients’, which permits us not to reassess under the new standard our prior conclusions about lease identification, lease classification and initial direct costs. We do not expect to elect the use-of hindsight or the practical expedient pertaining to land easements; the latter not being applicable to us. The new standard also provides practical expedients for an entity’s ongoing accounting. We currently expect to elect the short-term lease recognition exemption for all leases that qualify which means we will not recognize right-of-use (“ROU”) assets or lease liabilities for these leases, and this includes not recognizing ROU assets or lease liabilities for existing short-term leases of those assets in transition. We also currently expect to elect the practical expedient to not separate lease and non-lease components for all leases. We expect that this standard will have a material effect on our financial statements. While we continue to assess all of the effects of adoption, we currently believe the most significant effects relate to the recognition of new ROU assets and lease liabilities on our balance sheet for our existing operating leases. We are in the process of determining the financial statement impact and are currently unable to estimate the extent of the impact on our consolidated financial statements. In February 2018, the FASB issued ASU 2018-02, Income Statement – Reporting Comprehensive Income (Topic 220) In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350) Significant Accounting Policies Except for the accounting policies for revenue recognition and deferred commissions that were updated as a result of adopting ASU 2014-09, there were no material changes in our significant accounting policies during the nine months ended September 30, 2018. See Note A to the consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2017, as filed with the SEC on February 26, 2018, for additional information regarding our significant accounting policies. Revenue Recognition We derive our revenues primarily from the following revenue streams (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Recurring revenues: Fulfillment $ 48,482 $ 41,962 $ 140,326 $ 120,754 Analytics 8,750 8,679 25,639 25,517 Other 1,412 1,257 3,969 3,721 Recurring Revenues 58,644 51,898 169,934 149,992 One-time revenues 4,224 4,159 13,117 12,036 $ 62,868 $ 56,057 $ 183,051 $ 162,028 Revenues are recognized when our services are made available to our customers, in an amount that reflects the consideration we are contractually and legally entitled to in exchange for those services. We determine revenue recognition through the following steps: - Identification of the contract, or contracts, with a customer - Identification of the performance obligations in the contract - Determination of the transaction price - Allocation of the transaction price to the performance obligations in the contract - Recognition of revenue when, or as, we satisfy a performance obligation Recurring Revenues Recurring revenues consists of recurring subscriptions from customers that utilize our Fulfillment, Analytics and Other cloud-based supply chain management solutions. Revenue for these solutions is generally recognized on a ratable basis over the contract term beginning on the date that our service is made available to the customer. Our contracts with our recurring revenue customers are recurring in nature, ranging from monthly to annual, and generally allow the customer to cancel the contract for any reason with 30 to 90 days’ notice. Timing of billings varies by customer and by contract type and are either in advance or within 30 days of the service being performed. The deferred revenue liabilities for recurring revenue contracts are for one year or less and recognized on a ratable basis over the contract term. We have applied the optional exemption under ASC 606-10-50-14(a) and will not disclose information about the remaining performance obligations for contracts which have original durations of one year or less. One-time Revenues One-time revenues consist of set-up fees from customers and miscellaneous one-time fees. Set-up fees are specific for each connection a customer has with a trading partner and many of our customers have connections with numerous trading partners. Set-up fees related to our cloud-based supply chain management solutions are nonrefundable upfront fees that are necessary for our customers to utilize our cloud-based services. These set-up fees do not provide any standalone value to our customers. Except for our Analytics platform, we have determined the set-up fees represent a material renewal option right to our customers as they will not be incurred again upon renewal. These set-up fees and related costs are deferred and recognized ratably over two years, which is the estimated connection life between the customer and the trading partner. For our Analytics platform, we have determined the set-up fees do not represent a material customer renewal right and, as such, are deferred and recognized ratably over the estimated initial contract term, which is one year. The table below presents the activity of the portion of the deferred revenue liability relating to set-up fees (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Balances, at beginning of period $ 9,886 $ 10,280 $ 10,031 $ 9,995 Invoiced set-up fees 2,697 2,450 7,807 8,063 Amortized set-up fees (2,596 ) (2,634 ) (7,851 ) (7,962 ) Balances, at end of period $ 9,987 $ 10,096 $ 9,987 $ 10,096 The entire balance of set-up fees will be recognized within two years and, as such, current amounts will be recognized in the next 1-12 months and long-term amounts will be recognized in the next 13-24 months. Miscellaneous one-time fees consist of professional services and testing and certification. The deferred revenue liability for these one-time fees are for one year or less and recognized at the time service is provided. We have applied the optional exemption under ASC 606-10-50-14(a) and will not disclose information about the remaining performance obligations for contracts which have original durations of one year or less. Deferred Costs Deferred costs consist of costs to obtain customer contracts, such as commissions paid to sales personnel and to third-party partners for customer referrals, and costs to fulfill customer contracts, such as customer implementation costs. Sales commissions relating to recurring revenues are considered incremental and recoverable costs of obtaining a contract with our customer. These commissions are calculated based on estimated annual recurring revenue to be generated over the customer’s initial contract year. These costs are deferred and amortized over the expected period of benefit which we have determined to be two years. Amortization expense is included in sales and marketing expenses in the accompanying condensed consolidated statements of operations. The table below presents the activity of deferred costs and amortization of set-up fees (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Balances, at beginning of period $ 42,544 $ 35,332 $ 39,933 $ 32,117 Incurred deferred costs 12,391 11,294 36,807 32,142 Amortized deferred costs (11,204 ) (9,316 ) (33,009 ) (26,949 ) Balances, at end of period $ 43,731 $ 37,310 $ 43,731 $ 37,310 There was no impairment loss in relation to the costs capitalized for the periods presented.

Financial Instruments

Financial Instruments	9 Months Ended
	Sep. 30, 2018
Disclosure Text Block Supplement [Abstract]
Financial Instruments	NOTE B – Financial Instruments We invest primarily in money market funds, certificates of deposit, highly liquid debt instruments of the U.S. government and U.S. corporate debt securities. All highly liquid investments with original maturities of 90 days or less are classified as cash equivalents. All investments with original maturities greater than 90 days and remaining maturities less than one year from the balance sheet date are classified as short-term investments. Investments with remaining maturities of more than one year from the balance sheet date are classified as long-term investments. Our short- and long-term marketable securities are classified as available-for-sale. We intend to hold marketable securities until maturity; however, we may sell these securities at any time for use in current operations or for other purposes. Consequently, we may or may not keep securities with stated holding periods to maturity. Our marketable securities are carried at fair value and unrealized gains and losses on these investments, net of taxes, are included in accumulated other comprehensive loss in the condensed consolidated balance sheets. Realized gains or losses are included in other income (expense), net, in the condensed consolidated statements of comprehensive income. When a determination has been made that an other-than-temporary decline in fair value has occurred, the amount of the decline that is related to a credit loss is realized and is included in other income (expense), net, in the condensed consolidated statements of comprehensive income. Cash equivalents and short- and long-term investments consisted of the following (in thousands): September 30, 2018 Amortized Unrealized Fair Cost Gains (Losses) Value Cash equivalents: Money market funds $ 121,594 $ — $ 121,594 Certificate of deposit 7,224 — 7,224 Marketable securities: Corporate bonds 12,642 51 12,693 Commercial paper 17,323 57 17,380 U.S. treasury securities 12,300 (22 ) 12,278 $ 171,083 $ 86 $ 171,169 Due within one year $ 166,248 Due within two years 4,921 Total $ 171,169 December 31, 2017 Amortized Unrealized Fair Cost Gains (Losses) Value Cash equivalents: Money market funds $ 104,544 $ — $ 104,544 Certificate of deposit 7,814 — 7,814 Marketable securities: Corporate bonds 17,758 (57 ) 17,701 Commercial paper 7,456 20 7,476 U.S. treasury securities 12,381 26 12,407 $ 149,953 $ (11 ) $ 149,942 Due within one year $ 144,736 Due within two years 5,206 Total $ 149,942 We do not believe any of the unrealized losses represent an other-than-temporary impairment based on our valuation of available evidence as of September 30, 2018. We expect to receive the full principal and interest on all of these cash equivalents, certificate of deposit and marketable securities. Fair Value Measurements We measure certain financial assets at fair value on a recurring basis based on a fair value hierarchy that requires us to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. A financial instrument’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The three levels of inputs that may be used to measure fair value are: • Level 1 – quoted prices in active markets for identical assets or liabilities. • Level 2 – observable inputs other than Level 1 prices, such as: (a) quoted prices for similar assets or liabilities, (b) quoted prices in markets with insufficient volume or infrequent transactions (less active markets), or (c) model-derived valuations in which all significant inputs are observable or can be derived principally from or corroborated by observable market data for substantially the full term of the assets or liabilities. We obtain the fair values of our level 2 available-for-sale securities from a professional pricing service. • Level 3 – unobservable inputs to the valuation methodology that are significant to the measurement of fair value of assets or liabilities. The following table presents information about our financial assets that are measured at fair value on a recurring basis and indicates the fair value hierarchy of the valuation techniques utilized to determine such fair value (in thousands): September 30, 2018 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 121,594 $ — $ — $ 121,594 Certificate of deposit 7,224 — — 7,224 Marketable securities: Corporate bonds — 12,693 — 12,693 Commercial paper — 17,380 — 17,380 U.S. treasury securities — 12,278 — 12,278 Total $ 128,818 $ 42,351 $ — $ 171,169 December 31, 2017 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 104,544 $ — $ — $ 104,544 Certificate of deposit 7,814 — — 7,814 Marketable securities: Corporate bonds — 17,700 — 17,700 Commercial paper — 7,477 — 7,477 U.S. treasury securities — 12,407 — 12,407 Total $ 112,358 $ 37,584 $ — $ 149,942

Goodwill and Intangible Assets,

Goodwill and Intangible Assets, net	9 Months Ended
	Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets, net	NOTE C – Goodwill and Intangible Assets, net The changes in the net carrying amount of goodwill for the nine months ended September 30, 2018 are as follows (in thousands): 2018 Balances, January 1 $ 51,613 Goodwill acquired during the period — Foreign currency translation adjustments (1,111 ) Balances, September 30 $ 50,502 Intangible assets subject to amortization primarily include subscriber relationships, non-competition agreements and acquired technology and are amortized over their respective useful lives (ranging from 1 to 9 years). Intangible assets, net of amortization, included the following (in thousands): September 30, 2018 Foreign Carrying Accumulated Currency Amount Amortization Translation Net Subscriber relationships $ 35,512 $ (22,710 ) $ (64 ) $ 12,738 Non-competition agreements 2,560 (2,204 ) $ (13 ) 343 Technology and other 2,289 (1,859 ) $ (20 ) 410 $ 40,361 $ (26,773 ) $ (97 ) $ 13,491 December 31, 2017 Foreign Carrying Accumulated Currency Amount Amortization Translation Net Subscriber relationships $ 34,350 $ (19,592 ) $ 614 $ 15,372 Non-competition agreements 2,499 (2,058 ) 45 486 Technology and other 2,130 (1,518 ) 59 671 $ 38,979 $ (23,168 ) $ 718 $ 16,529 Total amortization expense for intangible assets during the three months ended September 30, 2018 and 2017 was $0.9 million and $1.1 million, respectively. Total amortization expense for intangible assets during the nine months ended September 30, 2018 and 2017 was $3.1 million and $3.5 million, respectively. Remainder of 2018 $ 930 2019 3,716 2020 3,361 2021 2,521 2022 1,449 Thereafter 1,514 $ 13,491

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE D – Commitments and Contingencies Operating Leases At September 30, 2018, our future minimum payments under operating leases were as follows (in thousands): Remainder of 2018 $ 1,012 2019 4,146 2020 3,476 2021 4,345 2022 4,035 Thereafter 8,671 $ 25,685

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	NOTE E – Stock-Based Compensation Our equity compensation plans provide for the grant of incentive and nonqualified stock options, restricted stock awards, restricted stock units and performance stock units to employees, non-employee directors and other consultants who provide services to us. We also provide an employee stock purchase plan and 401(k) stock match. Restricted stock awards result in the issuance of new shares when granted. For other stock-based awards, new shares are issued when the award is exercised, vested or released according to the terms of the agreement. In January 2018, 1,027,620 additional shares were reserved for future issuance under our 2010 Equity Incentive Plan. At September 30, 2018, there were approximately 5.3 million shares available for grant under approved equity compensation plans. We recognize stock-based compensation expense on a straight-line basis over the vesting period, except for expense relating to retirement-eligible employees, which is recognized immediately upon the employee becoming retirement-eligible. We recorded stock-based compensation expense of $3.3 million and $10.0 million for the three and nine months ended September 30, 2018 and $2.3 million and $6.8 million for the three and nine months ended September 30, 2017, respectively. This expense was allocated in the condensed consolidated statements of comprehensive income as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Cost of revenues $ 535 $ 494 $ 1,587 $ 1,414 Operating expenses Sales and marketing 691 565 2,054 1,656 Research and development 287 241 973 698 General and administrative 1,753 1,047 5,364 3,065 Total stock-based compensation expense $ 3,266 $ 2,347 $ 9,978 $ 6,833 Stock-based compensation expense by plan type was as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Stock options $ 677 $ 943 $ 2,670 $ 2,817 Performance share units 74 — 960 — Restricted stock units 1,976 1,173 4,727 3,334 Restricted stock awards 137 79 352 238 Employee stock purchase plan 109 152 332 444 401(k) stock match 293 — 937 — Total stock-based compensation expense $ 3,266 $ 2,347 $ 9,978 $ 6,833 As of September 30, 2018, there was approximately $14.3 million of unrecognized stock-based compensation expense under our equity compensation plans, which is expected to be recognized on a straight-line basis over a weighted average period of 2.6 Stock Options Stock options generally vest over four years and have a contractual term of seven to ten years from the date of grant. Our stock option activity was as follows: Weighted Average Options Exercise Price (#) ($/share) Outstanding at December 31, 2017 1,097,331 $ 47.60 Granted 181,472 59.88 Exercised (286,237 ) 41.23 Forfeited (60,270 ) 56.71 Outstanding at September 30, 2018 932,296 51.35 Of the total outstanding options at September 30, 2018, 594,300 were exercisable with a weighted average exercise price of $48.92 per share. The total outstanding options had a weighted average remaining contractual life of 3.3 The weighted average grant date fair value of options granted during the first nine months of 2018 was $19.48. This was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions: Volatility 34.9 % Dividend yield 0 % Life (in years) 4.4 Risk-free interest rate 2.53 % Performance Share Units and Restricted Stock Units and Awards In February 2017, our executive officers were granted performance share unit (“PSU”) awards with vesting contingent on successful attainment of pre-determined revenue targets over the course of a three-year performance period (fiscal years 2017 – 2019). The fair value is measured as the number of performance shares expected to be earned multiplied by the grant date fair value of our shares. The number of performance shares expected to vest during the current service period is estimated and the fair value of those shares is recognized over the remaining service period less any amounts already recognized. In February 2018, our executive officers were granted PSU awards with vesting contingent on the Company’s total shareholder return as compared to indexed total shareholder return over the course of a three-year performance period (fiscal years 2018 – 2020). The grant date fair value was estimated using a Monte Carlo simulation that utilizes multiple input variables that determine the probability of satisfying the performance conditions stipulated in the award and calculates the fair market value for the performance stock units granted. Expense is recognized on a straight-line basis over the vesting period, regardless of whether the market condition is satisfied. Restricted stock units vest over four years and, upon vesting, the holder is entitled to receive shares of our common stock. With restricted stock awards, shares of our common stock are issued when the award is granted and the restrictions lapse over one year. Activity for our performance share units and restricted stock units was as follows: Performance Share and Weighted Average Restricted Stock Units Grant Date Fair Value (#) ($/share) Outstanding at December 31, 2017 321,912 $ 55.16 Granted 156,933 63.09 Vested and common stock issued (81,427 ) 56.32 Forfeited (34,318 ) 54.91 Outstanding at September 30, 2018 363,100 58.35 The number of restricted stock units outstanding at September 30, 2018 included 38,321 units that have vested, but for which shares of common stock have not yet been issued pursuant to the terms of the agreement. With restricted stock awards, shares of our common stock are issued when the award is granted and the restrictions lapse over one year. Restricted Stock Weighted Average Grant Awards (#) Date Fair Value ($/share) Outstanding at December 31, 2017 1,368 $ 58.29 Restricted common stock issued 7,304 74.43 Restrictions lapsed (5,016 ) 70.03 Forfeited — — Outstanding at September 30, 2018 3,656 74.43 Employee Stock Purchase Plan Our employee stock purchase plan a llows participating employees to purchase shares of our common stock at a discount through payroll deductions. The plan is available to all employees subject to certain eligibility requirements. Participating employees may purchase common stock, on a voluntary after-tax basis, at a price that is the lower of 85% of the fair market value of one share of common stock at the beginning or end of each stock purchase period. The plan consists of two six-month offering periods, beginning on January 1 and July 1 of each calendar year, respectively. A total of 1.0 million shares of common stock are reserved for issuance under the plan. For the offering period that began on January 1, 2018 and ended on June 30, 2018, we withheld $0.8 million from employees participating in the plan which were used to purchase 20,243 shares. For the offering period that began on July 1, 2018 and will end on December 31, 2018, we have withheld $0.5 million as of September 30, 2018 from employees participating in the plan. The fair value was estimated based on the market price of our common stock at the beginning of the offering period using the Black-Scholes option pricing model with the following assumptions: Volatility 26.5 % Dividend yield 0 % Life (in years) 0.5 Risk-free interest rate 1.50 % 401(k) Stock Match We sponsor a 401(k) retirement savings plan for our U.S. employees where employees can contribute up to 100% of their compensation, subject to the limits established by law. In 2018, we increased our match to 50% of the employee’s elective deferrals, up to the first 6% of the employee’s pre-tax compensation for each pay period. A portion of our match is in company stock, which is purchased from the open market by our plan provider and immediately deposited into the employee’s 401(k) account.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	NOTE F – Income Taxes We record our interim provision for income taxes by applying our estimated annual effective tax rate to our year-to-date pretax income and adjust the provision for discrete tax items recorded in the period. Differences between our effective tax rate and statutory tax rates are primarily due to the impact of permanently non-deductible expenses partially offset by the federal research and development credits. Additionally, excess tax benefits generated upon settlement or exercise of stock awards are recognized as a reduction to income tax expense as a discrete tax item in the quarter that the event occurs creating potentially significant fluctuation in tax expense by quarter and by year. Our provisions for income taxes include current foreign and state income tax expense, as well as deferred tax expense. As of September 30, 2018 we do not have any unrecognized tax benefits nor any accrued interest or tax penalties. Tax Act The Tax Act, which was enacted on December 22, 2017, included broad and complex changes to the U.S tax code. The Tax Act reduced the corporate federal income tax rate to 21.0% effective January 1, 2018 and established a mandatory tax on previously untaxed foreign earnings and profits (“E&P”). The Tax Act expanded the deduction limits on executive compensation under Section 162(m) and included transition rules for previously awarded compensation. We have completed our evaluation of the impact of the Tax Act on previously untaxed foreign E&P and the deferred tax liability for withholding taxes on dividends. We have also completed our evaluation of the impact of the expanded Section 162(m) limitations and related transition rules on our deferred tax assets related to stock compensation. As a result of our evaluation, there was no material adjustment to our previously calculated discrete income tax expense relating to the Tax Act.

Net Income Per Share

Net Income Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Net Income Per Share	NOTE G – Net Income Per Share Basic net income per share has been computed using the weighted average number of shares of common stock outstanding during each period. Diluted net income per share also includes the impact of our outstanding potential common shares, including options and restricted stock units. Potential common shares that are anti-dilutive are excluded from the calculation of diluted net income per share. The following table presents the components of the computation of basic and diluted net income per share for the periods indicated (in thousands, except per share amounts): Three Months Ended Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Numerator Net income $ 8,061 $ 2,176 $ 16,731 $ 7,129 Denominator Weighted average common shares outstanding, basic 17,219 17,223 17,167 17,192 Options to purchase common stock 395 152 293 169 Restricted stock units 127 35 97 33 Weighted average common shares outstanding, diluted 17,741 17,410 17,557 17,394 Net income per share Basic $ 0.47 $ 0.13 $ 0.97 $ 0.42 Diluted $ 0.45 $ 0.13 $ 0.95 $ 0.41 Antidilutive shares (in thousands) — 267 27 267

General (Policies)

General (Policies)	9 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of SPS Commerce, Inc. and its subsidiaries. All intercompany accounts and transactions have been eliminated in the unaudited condensed consolidated financial statements, which Effective January 1, 2018, we adopted the requirements of Accounting Standards Update ("ASU") No. 2014-09 (“ASU 2014-09”), Revenue from Contracts with Customers (Topic 606)
Use of Estimates	Use of Estimates Preparing financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU 2014-09 which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This guidance replaced most existing revenue recognition guidance in GAAP. Topic 606 also includes Subtopic 340-40, Other Assets and Deferred Costs – Contracts with Customers We adopted the new standard effective January 1, 2018, on a retrospective basis. The new standard did not impact our recognition of the recurring revenue received from customers for our cloud-based supply chain solutions; however, the adoption of the new standard impacted our accounting for certain upfront set-up fees, the periods over which the related revenues are recognized and the timing of revenue recognition for these set-up fees. The adoption of the new standard also impacted our accounting for certain costs to obtain our contracts, specifically related to the periods over which commissions are recognized as well as the timing of cost recognition. Selected condensed consolidated balance sheet line items, which reflect the adoption of ASU 2014-09 are as follows (in thousands): December 31, 2017 As previously reported Adjustments As adjusted ASSETS Deferred costs $ 25,091 $ 4,875 $ 29,966 Deferred costs, non-current 6,770 3,197 9,967 Deferred income tax asset 17,551 (3,854 ) 13,697 LIABILITIES Accrued compensation 15,886 (658 ) 15,228 Deferred revenue 16,407 1,456 17,863 Deferred revenue, non-current 10,602 (7,871 ) 2,731 STOCKHOLDERS’ EQUITY Accumulated deficit (19,902 ) 11,291 (8,611 ) Selected unaudited condensed consolidated statement of operations line items, which reflect the adoption of ASU 2014-09 are as follows (in thousands): For the three months ended September 30, 2017 As previously reported Adjustments As adjusted Revenues 56,150 (93 ) 56,057 Operating expenses Sales and marketing 18,239 (601 ) 17,638 Income from operations 2,846 508 3,354 Income tax expense 1,058 197 1,255 Net income $ 1,865 $ 311 $ 2,176 Net income per share Basic $ 0.11 $ 0.02 $ 0.13 Diluted $ 0.11 $ 0.02 $ 0.13 For the nine months ended September 30, 2017 As previously reported Adjustments As adjusted Revenues 162,366 (338 ) 162,028 Operating expenses Sales and marketing 54,059 (1,078 ) 52,981 Income from operations 8,949 740 9,689 Income tax expense 2,636 272 2,908 Net income $ 6,661 $ 468 $ 7,129 Net income per share Basic $ 0.39 $ 0.03 $ 0.42 Diluted $ 0.38 $ 0.03 $ 0.41 Selected unaudited condensed consolidated statement of cash flows line items, which reflect the adoption of ASU 2014-09 are as follows (in thousands): For the nine months ended September 30, 2017 As previously reported Adjustments As adjusted Cash flows from operating activities Net income $ 6,661 $ 468 $ 7,129 Reconciliation of net income to net cash provided by operating activities Deferred income taxes 1,968 272 2,240 Changes in assets and liabilities Deferred costs (4,487 ) (701 ) (5,188 ) Accrued compensation (1,140 ) (377 ) (1,517 ) Deferred revenue 4,932 338 5,270 Net cash provided by operating activities 21,972 — 21,972 In March 2018, we adopted FASB ASU 2018-05, Income Taxes (Topic 740): Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118
Accounting Pronouncements Not Yet Adopted	Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU 2016-02, Leases We will adopt the new standard on January 1, 2019 and use the effective date as our date of initial application. Consequently, financial information will not be updated and the disclosures required under the new standard will not be provided for dates and periods before January 1, 2019. The new standard provides several optional practical expedients in transition. We expect to elect the ‘package of practical expedients’, which permits us not to reassess under the new standard our prior conclusions about lease identification, lease classification and initial direct costs. We do not expect to elect the use-of hindsight or the practical expedient pertaining to land easements; the latter not being applicable to us. The new standard also provides practical expedients for an entity’s ongoing accounting. We currently expect to elect the short-term lease recognition exemption for all leases that qualify which means we will not recognize right-of-use (“ROU”) assets or lease liabilities for these leases, and this includes not recognizing ROU assets or lease liabilities for existing short-term leases of those assets in transition. We also currently expect to elect the practical expedient to not separate lease and non-lease components for all leases. We expect that this standard will have a material effect on our financial statements. While we continue to assess all of the effects of adoption, we currently believe the most significant effects relate to the recognition of new ROU assets and lease liabilities on our balance sheet for our existing operating leases. We are in the process of determining the financial statement impact and are currently unable to estimate the extent of the impact on our consolidated financial statements. In February 2018, the FASB issued ASU 2018-02, Income Statement – Reporting Comprehensive Income (Topic 220) In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350)
Significant Accounting Policies	Significant Accounting Policies Except for the accounting policies for revenue recognition and deferred commissions that were updated as a result of adopting ASU 2014-09, there were no material changes in our significant accounting policies during the nine months ended September 30, 2018. See Note A to the consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2017, as filed with the SEC on February 26, 2018, for additional information regarding our significant accounting policies.
Revenue Recognition	Revenue Recognition We derive our revenues primarily from the following revenue streams (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Recurring revenues: Fulfillment $ 48,482 $ 41,962 $ 140,326 $ 120,754 Analytics 8,750 8,679 25,639 25,517 Other 1,412 1,257 3,969 3,721 Recurring Revenues 58,644 51,898 169,934 149,992 One-time revenues 4,224 4,159 13,117 12,036 $ 62,868 $ 56,057 $ 183,051 $ 162,028 Revenues are recognized when our services are made available to our customers, in an amount that reflects the consideration we are contractually and legally entitled to in exchange for those services. We determine revenue recognition through the following steps: - Identification of the contract, or contracts, with a customer - Identification of the performance obligations in the contract - Determination of the transaction price - Allocation of the transaction price to the performance obligations in the contract - Recognition of revenue when, or as, we satisfy a performance obligation Recurring Revenues Recurring revenues consists of recurring subscriptions from customers that utilize our Fulfillment, Analytics and Other cloud-based supply chain management solutions. Revenue for these solutions is generally recognized on a ratable basis over the contract term beginning on the date that our service is made available to the customer. Our contracts with our recurring revenue customers are recurring in nature, ranging from monthly to annual, and generally allow the customer to cancel the contract for any reason with 30 to 90 days’ notice. Timing of billings varies by customer and by contract type and are either in advance or within 30 days of the service being performed. The deferred revenue liabilities for recurring revenue contracts are for one year or less and recognized on a ratable basis over the contract term. We have applied the optional exemption under ASC 606-10-50-14(a) and will not disclose information about the remaining performance obligations for contracts which have original durations of one year or less. One-time Revenues One-time revenues consist of set-up fees from customers and miscellaneous one-time fees. Set-up fees are specific for each connection a customer has with a trading partner and many of our customers have connections with numerous trading partners. Set-up fees related to our cloud-based supply chain management solutions are nonrefundable upfront fees that are necessary for our customers to utilize our cloud-based services. These set-up fees do not provide any standalone value to our customers. Except for our Analytics platform, we have determined the set-up fees represent a material renewal option right to our customers as they will not be incurred again upon renewal. These set-up fees and related costs are deferred and recognized ratably over two years, which is the estimated connection life between the customer and the trading partner. For our Analytics platform, we have determined the set-up fees do not represent a material customer renewal right and, as such, are deferred and recognized ratably over the estimated initial contract term, which is one year. The table below presents the activity of the portion of the deferred revenue liability relating to set-up fees (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Balances, at beginning of period $ 9,886 $ 10,280 $ 10,031 $ 9,995 Invoiced set-up fees 2,697 2,450 7,807 8,063 Amortized set-up fees (2,596 ) (2,634 ) (7,851 ) (7,962 ) Balances, at end of period $ 9,987 $ 10,096 $ 9,987 $ 10,096 The entire balance of set-up fees will be recognized within two years and, as such, current amounts will be recognized in the next 1-12 months and long-term amounts will be recognized in the next 13-24 months. Miscellaneous one-time fees consist of professional services and testing and certification. The deferred revenue liability for these one-time fees are for one year or less and recognized at the time service is provided. We have applied the optional exemption under ASC 606-10-50-14(a) and will not disclose information about the remaining performance obligations for contracts which have original durations of one year or less.
Deferred Costs	Deferred Costs Deferred costs consist of costs to obtain customer contracts, such as commissions paid to sales personnel and to third-party partners for customer referrals, and costs to fulfill customer contracts, such as customer implementation costs. Sales commissions relating to recurring revenues are considered incremental and recoverable costs of obtaining a contract with our customer. These commissions are calculated based on estimated annual recurring revenue to be generated over the customer’s initial contract year. These costs are deferred and amortized over the expected period of benefit which we have determined to be two years. Amortization expense is included in sales and marketing expenses in the accompanying condensed consolidated statements of operations. The table below presents the activity of deferred costs and amortization of set-up fees (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Balances, at beginning of period $ 42,544 $ 35,332 $ 39,933 $ 32,117 Incurred deferred costs 12,391 11,294 36,807 32,142 Amortized deferred costs (11,204 ) (9,316 ) (33,009 ) (26,949 ) Balances, at end of period $ 43,731 $ 37,310 $ 43,731 $ 37,310 There was no impairment loss in relation to the costs capitalized for the periods presented.

General (Tables)

General (Tables)	9 Months Ended
	Sep. 30, 2018
Summary of Revenues by Revenue Stream	We derive our revenues primarily from the following revenue streams (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Recurring revenues: Fulfillment $ 48,482 $ 41,962 $ 140,326 $ 120,754 Analytics 8,750 8,679 25,639 25,517 Other 1,412 1,257 3,969 3,721 Recurring Revenues 58,644 51,898 169,934 149,992 One-time revenues 4,224 4,159 13,117 12,036 $ 62,868 $ 56,057 $ 183,051 $ 162,028
Summary of Deferred Revenue Liability Relating to Set-Up Fees	The table below presents the activity of the portion of the deferred revenue liability relating to set-up fees (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Balances, at beginning of period $ 9,886 $ 10,280 $ 10,031 $ 9,995 Invoiced set-up fees 2,697 2,450 7,807 8,063 Amortized set-up fees (2,596 ) (2,634 ) (7,851 ) (7,962 ) Balances, at end of period $ 9,987 $ 10,096 $ 9,987 $ 10,096
Summary of Deferred Costs and Amortization of Set-up Fees	The table below presents the activity of deferred costs and amortization of set-up fees (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Balances, at beginning of period $ 42,544 $ 35,332 $ 39,933 $ 32,117 Incurred deferred costs 12,391 11,294 36,807 32,142 Amortized deferred costs (11,204 ) (9,316 ) (33,009 ) (26,949 ) Balances, at end of period $ 43,731 $ 37,310 $ 43,731 $ 37,310
ASU 2014-09 [Member]
Adoption of Accounting Standard Changes on Financial Statements	Selected condensed consolidated balance sheet line items, which reflect the adoption of ASU 2014-09 are as follows (in thousands): December 31, 2017 As previously reported Adjustments As adjusted ASSETS Deferred costs $ 25,091 $ 4,875 $ 29,966 Deferred costs, non-current 6,770 3,197 9,967 Deferred income tax asset 17,551 (3,854 ) 13,697 LIABILITIES Accrued compensation 15,886 (658 ) 15,228 Deferred revenue 16,407 1,456 17,863 Deferred revenue, non-current 10,602 (7,871 ) 2,731 STOCKHOLDERS’ EQUITY Accumulated deficit (19,902 ) 11,291 (8,611 ) Selected unaudited condensed consolidated statement of operations line items, which reflect the adoption of ASU 2014-09 are as follows (in thousands): For the three months ended September 30, 2017 As previously reported Adjustments As adjusted Revenues 56,150 (93 ) 56,057 Operating expenses Sales and marketing 18,239 (601 ) 17,638 Income from operations 2,846 508 3,354 Income tax expense 1,058 197 1,255 Net income $ 1,865 $ 311 $ 2,176 Net income per share Basic $ 0.11 $ 0.02 $ 0.13 Diluted $ 0.11 $ 0.02 $ 0.13 For the nine months ended September 30, 2017 As previously reported Adjustments As adjusted Revenues 162,366 (338 ) 162,028 Operating expenses Sales and marketing 54,059 (1,078 ) 52,981 Income from operations 8,949 740 9,689 Income tax expense 2,636 272 2,908 Net income $ 6,661 $ 468 $ 7,129 Net income per share Basic $ 0.39 $ 0.03 $ 0.42 Diluted $ 0.38 $ 0.03 $ 0.41 Selected unaudited condensed consolidated statement of cash flows line items, which reflect the adoption of ASU 2014-09 are as follows (in thousands): For the nine months ended September 30, 2017 As previously reported Adjustments As adjusted Cash flows from operating activities Net income $ 6,661 $ 468 $ 7,129 Reconciliation of net income to net cash provided by operating activities Deferred income taxes 1,968 272 2,240 Changes in assets and liabilities Deferred costs (4,487 ) (701 ) (5,188 ) Accrued compensation (1,140 ) (377 ) (1,517 ) Deferred revenue 4,932 338 5,270 Net cash provided by operating activities 21,972 — 21,972

Financial Instruments (Tables)

Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2018
Financial Instruments Owned At Fair Value [Abstract]
Summary of Cash Equivalents and Short and Long-term Investments	Cash equivalents and short- and long-term investments consisted of the following (in thousands): September 30, 2018 Amortized Unrealized Fair Cost Gains (Losses) Value Cash equivalents: Money market funds $ 121,594 $ — $ 121,594 Certificate of deposit 7,224 — 7,224 Marketable securities: Corporate bonds 12,642 51 12,693 Commercial paper 17,323 57 17,380 U.S. treasury securities 12,300 (22 ) 12,278 $ 171,083 $ 86 $ 171,169 Due within one year $ 166,248 Due within two years 4,921 Total $ 171,169 December 31, 2017 Amortized Unrealized Fair Cost Gains (Losses) Value Cash equivalents: Money market funds $ 104,544 $ — $ 104,544 Certificate of deposit 7,814 — 7,814 Marketable securities: Corporate bonds 17,758 (57 ) 17,701 Commercial paper 7,456 20 7,476 U.S. treasury securities 12,381 26 12,407 $ 149,953 $ (11 ) $ 149,942 Due within one year $ 144,736 Due within two years 5,206 Total $ 149,942
Summary of Financial Assets Measured at Fair Value on a Recurring Basis	The following table presents information about our financial assets that are measured at fair value on a recurring basis and indicates the fair value hierarchy of the valuation techniques utilized to determine such fair value (in thousands): September 30, 2018 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 121,594 $ — $ — $ 121,594 Certificate of deposit 7,224 — — 7,224 Marketable securities: Corporate bonds — 12,693 — 12,693 Commercial paper — 17,380 — 17,380 U.S. treasury securities — 12,278 — 12,278 Total $ 128,818 $ 42,351 $ — $ 171,169 December 31, 2017 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 104,544 $ — $ — $ 104,544 Certificate of deposit 7,814 — — 7,814 Marketable securities: Corporate bonds — 17,700 — 17,700 Commercial paper — 7,477 — 7,477 U.S. treasury securities — 12,407 — 12,407 Total $ 112,358 $ 37,584 $ — $ 149,942

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets, net (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Changes in Net Carrying Amount of Goodwill	The changes in the net carrying amount of goodwill for the nine months ended September 30, 2018 are as follows (in thousands): 2018 Balances, January 1 $ 51,613 Goodwill acquired during the period — Foreign currency translation adjustments (1,111 ) Balances, September 30 $ 50,502
Intangible Assets Subject to Amortization	Intangible assets subject to amortization primarily include subscriber relationships, non-competition agreements and acquired technology and are amortized over their respective useful lives (ranging from 1 to 9 years). Intangible assets, net of amortization, included the following (in thousands): September 30, 2018 Foreign Carrying Accumulated Currency Amount Amortization Translation Net Subscriber relationships $ 35,512 $ (22,710 ) $ (64 ) $ 12,738 Non-competition agreements 2,560 (2,204 ) $ (13 ) 343 Technology and other 2,289 (1,859 ) $ (20 ) 410 $ 40,361 $ (26,773 ) $ (97 ) $ 13,491 December 31, 2017 Foreign Carrying Accumulated Currency Amount Amortization Translation Net Subscriber relationships $ 34,350 $ (19,592 ) $ 614 $ 15,372 Non-competition agreements 2,499 (2,058 ) 45 486 Technology and other 2,130 (1,518 ) 59 671 $ 38,979 $ (23,168 ) $ 718 $ 16,529
Estimated Annual Amortization Expense Related to Intangible Assets Subject to Amortization	The estimated annual amortization expense related to intangible assets subject to amortization for the next five years is as follows (in thousands): Remainder of 2018 $ 930 2019 3,716 2020 3,361 2021 2,521 2022 1,449 Thereafter 1,514 $ 13,491

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Future Minimum Payments Under Operating Leases	At September 30, 2018, our future minimum payments under operating leases were as follows (in thousands): Remainder of 2018 $ 1,012 2019 4,146 2020 3,476 2021 4,345 2022 4,035 Thereafter 8,671 $ 25,685

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2018
Stock-Based Compensation Expense	This expense was allocated in the condensed consolidated statements of comprehensive income as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Cost of revenues $ 535 $ 494 $ 1,587 $ 1,414 Operating expenses Sales and marketing 691 565 2,054 1,656 Research and development 287 241 973 698 General and administrative 1,753 1,047 5,364 3,065 Total stock-based compensation expense $ 3,266 $ 2,347 $ 9,978 $ 6,833 Stock-based compensation expense by plan type was as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Stock options $ 677 $ 943 $ 2,670 $ 2,817 Performance share units 74 — 960 — Restricted stock units 1,976 1,173 4,727 3,334 Restricted stock awards 137 79 352 238 Employee stock purchase plan 109 152 332 444 401(k) stock match 293 — 937 — Total stock-based compensation expense $ 3,266 $ 2,347 $ 9,978 $ 6,833
Stock Option Activity	Stock options generally vest over four years and have a contractual term of seven to ten years from the date of grant. Our stock option activity was as follows: Weighted Average Options Exercise Price (#) ($/share) Outstanding at December 31, 2017 1,097,331 $ 47.60 Granted 181,472 59.88 Exercised (286,237 ) 41.23 Forfeited (60,270 ) 56.71 Outstanding at September 30, 2018 932,296 51.35
Weighted Average Grant Date Fair Value of Options Granted, Assumptions	The weighted average grant date fair value of options granted during the first nine months of 2018 was $19.48. This was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions: Volatility 34.9 % Dividend yield 0 % Life (in years) 4.4 Risk-free interest rate 2.53 %
Fair Value Estimation of Common Stock Using Black-Scholes Option Pricing Model, Assumptions	The fair value was estimated based on the market price of our common stock at the beginning of the offering period using the Black-Scholes option pricing model with the following assumptions: Volatility 26.5 % Dividend yield 0 % Life (in years) 0.5 Risk-free interest rate 1.50 %
Performance Share Units and Restricted Stock Units [Member]
Performance Share Units and Restricted Stock Units and Restricted Stock Awards	Activity for our performance share units and restricted stock units was as follows: Performance Share and Weighted Average Restricted Stock Units Grant Date Fair Value (#) ($/share) Outstanding at December 31, 2017 321,912 $ 55.16 Granted 156,933 63.09 Vested and common stock issued (81,427 ) 56.32 Forfeited (34,318 ) 54.91 Outstanding at September 30, 2018 363,100 58.35
Restricted Stock Award [Member]
Performance Share Units and Restricted Stock Units and Restricted Stock Awards	Our restricted stock awards activity was as follows: Restricted Stock Weighted Average Grant Awards (#) Date Fair Value ($/share) Outstanding at December 31, 2017 1,368 $ 58.29 Restricted common stock issued 7,304 74.43 Restrictions lapsed (5,016 ) 70.03 Forfeited — — Outstanding at September 30, 2018 3,656 74.43

Net Income Per Share (Tables)

Net Income Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Components of Computation of Basic and Diluted Net Income Per Share	The following table presents the components of the computation of basic and diluted net income per share for the periods indicated (in thousands, except per share amounts): Three Months Ended Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Numerator Net income $ 8,061 $ 2,176 $ 16,731 $ 7,129 Denominator Weighted average common shares outstanding, basic 17,219 17,223 17,167 17,192 Options to purchase common stock 395 152 293 169 Restricted stock units 127 35 97 33 Weighted average common shares outstanding, diluted 17,741 17,410 17,557 17,394 Net income per share Basic $ 0.47 $ 0.13 $ 0.97 $ 0.42 Diluted $ 0.45 $ 0.13 $ 0.95 $ 0.41 Antidilutive shares (in thousands) — 267 27 267

General - Condensed Consolidate

General - Condensed Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
ASSETS
Deferred costs	$ 33,134	$ 29,966
Deferred costs, non-current	10,597	9,967
Deferred income tax asset		13,697
LIABILITIES
Accrued compensation	15,498	15,228
Deferred revenue	24,948	17,863
Deferred revenue, non-current	2,685	2,731
STOCKHOLDERS’ EQUITY
Accumulated deficit	$ 8,120	(8,611)
ASU 2014-09 [Member] | As Previously Reported [Member]
ASSETS
Deferred costs		25,091
Deferred costs, non-current		6,770
Deferred income tax asset		17,551
LIABILITIES
Accrued compensation		15,886
Deferred revenue		16,407
Deferred revenue, non-current		10,602
STOCKHOLDERS’ EQUITY
Accumulated deficit		(19,902)
ASU 2014-09 [Member] | Adjustments [Member]
ASSETS
Deferred costs		4,875
Deferred costs, non-current		3,197
Deferred income tax asset		(3,854)
LIABILITIES
Accrued compensation		(658)
Deferred revenue		1,456
Deferred revenue, non-current		(7,871)
STOCKHOLDERS’ EQUITY
Accumulated deficit		$ 11,291

General - Unaudited Condensed C

General - Unaudited Condensed Consolidated Statement of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues	$ 62,868	$ 56,057	$ 183,051	$ 162,028
Operating expenses
Sales and marketing	16,952	17,638	54,023	52,981
Income from operations	8,257	3,354	18,522	9,689
Income tax expense	605	1,255	2,839	2,908
Net income	$ 8,061	$ 2,176	$ 16,731	$ 7,129
Net income per share
Basic	$ 0.47	$ 0.13	$ 0.97	$ 0.42
Diluted	$ 0.45	$ 0.13	$ 0.95	$ 0.41
ASU 2014-09 [Member] | As Previously Reported [Member]
Revenues		$ 56,150		$ 162,366
Operating expenses
Sales and marketing		18,239		54,059
Income from operations		2,846		8,949
Income tax expense		1,058		2,636
Net income		$ 1,865		$ 6,661
Net income per share
Basic		$ 0.11		$ 0.39
Diluted		$ 0.11		$ 0.38
ASU 2014-09 [Member] | Adjustments [Member]
Revenues		$ (93)		$ (338)
Operating expenses
Sales and marketing		(601)		(1,078)
Income from operations		508		740
Income tax expense		197		272
Net income		$ 311		$ 468
Net income per share
Basic		$ 0.02		$ 0.03
Diluted		$ 0.02		$ 0.03

General - Unaudited Condensed_2

General - Unaudited Condensed Consolidated Statement of Cash Flows (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net income	$ 8,061	$ 2,176	$ 16,731	$ 7,129
Reconciliation of net income to net cash provided by operating activities
Deferred income taxes			1,934	2,240
Changes in assets and liabilities
Deferred costs			(3,813)	(5,188)
Accrued compensation			(592)	(1,517)
Deferred revenue			7,039	5,270
Net cash provided by operating activities			$ 37,547	21,972
ASU 2014-09 [Member] | As Previously Reported [Member]
Cash flows from operating activities
Net income		1,865		6,661
Reconciliation of net income to net cash provided by operating activities
Deferred income taxes				1,968
Changes in assets and liabilities
Deferred costs				(4,487)
Accrued compensation				(1,140)
Deferred revenue				4,932
Net cash provided by operating activities				21,972
ASU 2014-09 [Member] | Adjustments [Member]
Cash flows from operating activities
Net income		$ 311		468
Reconciliation of net income to net cash provided by operating activities
Deferred income taxes				272
Changes in assets and liabilities
Deferred costs				(701)
Accrued compensation				(377)
Deferred revenue				$ 338

General - Summary of Revenues b

General - Summary of Revenues by Revenue Stream (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue Recognition [Line Items]
Revenues	$ 62,868	$ 56,057	$ 183,051	$ 162,028
Recurring Revenues [Member]
Revenue Recognition [Line Items]
Revenues	58,644	51,898	169,934	149,992
One-time Revenues [Member]
Revenue Recognition [Line Items]
Revenues	4,224	4,159	13,117	12,036
Fulfillment [Member] | Recurring Revenues [Member]
Revenue Recognition [Line Items]
Revenues	48,482	41,962	140,326	120,754
Analytics [Member] | Recurring Revenues [Member]
Revenue Recognition [Line Items]
Revenues	8,750	8,679	25,639	25,517
Other [Member] | Recurring Revenues [Member]
Revenue Recognition [Line Items]
Revenues	$ 1,412	$ 1,257	$ 3,969	$ 3,721

General - Additional Informatio

General - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018USD ($)
Schedule Of Accounting Policies [Line Items]
Earliest timing of billings	in advance
Latest timing of billings	30 days
Estimated connection life between customer and trading partner	2 years
Set up fees recognized period	2 years
Maximum recognition period for miscellaneous one-time fee	1 year
Deferred commission expected amortization period	2 years
Impairment loss in relation to costs capitalized	$ 0
Analytics Platform [Member]
Schedule Of Accounting Policies [Line Items]
Set up fees recognized period	1 year
Minimum [Member]
Schedule Of Accounting Policies [Line Items]
Customer contract cancellation period	30 days
Current amount recognition period of set up fees	1 month
Long term amount recognition period of set up fees	13 months
Maximum [Member]
Schedule Of Accounting Policies [Line Items]
Customer contract cancellation period	90 days
Deferred revenue recognition period	1 year
Contract period for remaining performance obligations for contracts in which the optional exemption under ASC 606-10-50-14(a) was applied	1 year
Current amount recognition period of set up fees	12 months
Long term amount recognition period of set up fees	24 months

General - Summary of Deferred R

General - Summary of Deferred Revenue Liability Relating to Set-Up Fees (Detail) - Set-Up Fees [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Deferred Revenue Arrangement [Line Items]
Balances, at beginning of period	$ 9,886	$ 10,280	$ 10,031	$ 9,995
Invoiced set-up fees	2,697	2,450	7,807	8,063
Amortized set-up fees	(2,596)	(2,634)	(7,851)	(7,962)
Balances, at end of period	$ 9,987	$ 10,096	$ 9,987	$ 10,096

General - Summary of Deferred C

General - Summary of Deferred Costs and Amortization of Set-up Fees (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Deferred Costs [Abstract]
Balances, at beginning of period	$ 42,544	$ 35,332	$ 39,933	$ 32,117
Incurred deferred costs	12,391	11,294	36,807	32,142
Amortized deferred costs	(11,204)	(9,316)	(33,009)	(26,949)
Balances, at end of period	$ 43,731	$ 37,310	$ 43,731	$ 37,310

Financial Instruments - Summary

Financial Instruments - Summary of Cash Equivalents and Short and Long-term Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financial Instruments [Member]
Schedule of Financial Instruments [Line Items]
Due within one year	$ 166,248	$ 144,736
Amortized Cost	171,083	149,953
Due within two years	4,921	5,206
Unrealized Gains (Losses)	86	(11)
Fair Value	171,169	149,942
Money Market Funds [Member]
Schedule of Financial Instruments [Line Items]
Amortized Cost	121,594	104,544
Fair Value	121,594	104,544
Certificate of Deposit [Member]
Schedule of Financial Instruments [Line Items]
Amortized Cost	7,224	7,814
Fair Value	7,224	7,814
Corporate Bonds [Member]
Schedule of Financial Instruments [Line Items]
Amortized Cost	12,642	17,758
Unrealized Gains (Losses)	51	(57)
Fair Value	12,693	17,701
Commercial Paper [Member]
Schedule of Financial Instruments [Line Items]
Amortized Cost	17,323	7,456
Unrealized Gains (Losses)	57	20
Fair Value	17,380	7,476
U.S. Treasury Securities [Member]
Schedule of Financial Instruments [Line Items]
Amortized Cost	12,300	12,381
Unrealized Gains (Losses)	(22)	26
Fair Value	$ 12,278	$ 12,407

Financial Instruments - Summa_2

Financial Instruments - Summary of Financial Assets Measured at Fair Value on a Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	$ 171,169	$ 149,942
Money Market Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	121,594	104,544
Certificate of Deposit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	7,224	7,814
Corporate Bonds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	12,693	17,700
Commercial Paper [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	17,380	7,477
U.S. Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	12,278	12,407
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	128,818	112,358
Level 1 [Member] | Money Market Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	121,594	104,544
Level 1 [Member] | Certificate of Deposit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	7,224	7,814
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	42,351	37,584
Level 2 [Member] | Corporate Bonds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	12,693	17,700
Level 2 [Member] | Commercial Paper [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	17,380	7,477
Level 2 [Member] | U.S. Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets fair value	$ 12,278	$ 12,407

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets, net - Schedule of Changes in Net Carrying Amount of Goodwill (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
Balances, January 1	$ 51,613
Foreign currency translation adjustments	(1,111)
Balances, September 30	$ 50,502

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets, net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 928	$ 1,128	$ 3,086	$ 3,460
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets useful life			1 year
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets useful life			9 years

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets, net - Intangible Assets Subject to Amortization (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Carrying Amount	$ 40,361	$ 38,979
Accumulated Amortization	(26,773)	(23,168)
Foreign Currency Translation	(97)	718
Net	13,491	16,529
Subscriber Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Carrying Amount	35,512	34,350
Accumulated Amortization	(22,710)	(19,592)
Foreign Currency Translation	(64)	614
Net	12,738	15,372
Non-competition Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Carrying Amount	2,560	2,499
Accumulated Amortization	(2,204)	(2,058)
Foreign Currency Translation	(13)	45
Net	343	486
Technology and Other [Member]
Finite-Lived Intangible Assets [Line Items]
Carrying Amount	2,289	2,130
Accumulated Amortization	(1,859)	(1,518)
Foreign Currency Translation	(20)	59
Net	$ 410	$ 671

Goodwill and Intangible Asset_6

Goodwill and Intangible Assets, net - Estimated Annual Amortization Expense Related to Intangible Assets Subject to Amortization (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Remainder of 2018	$ 930
2,019	3,716
2,020	3,361
2,021	2,521
2,022	1,449
Thereafter	1,514
Net	$ 13,491	$ 16,529

Commitments and Contingencies -

Commitments and Contingencies - Future Minimum Payments Under Operating Leases (Detail) $ in Thousands	Sep. 30, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
Remainder of 2018	$ 1,012
2,019	4,146
2,020	3,476
2,021	4,345
2,022	4,035
Thereafter	8,671
Operating leases, total	$ 25,685

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended	9 Months Ended
	Feb. 28, 2018	Feb. 28, 2017	Sep. 30, 2018USD ($)Offering$ / sharesshares	Sep. 30, 2017USD ($)	Jun. 30, 2018USD ($)shares	Sep. 30, 2018USD ($)Offering$ / sharesshares	Sep. 30, 2017USD ($)	Jan. 31, 2018shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant | shares			5,300,000			5,300,000
Stock-based compensation expense			$ 3,266	$ 2,347		$ 9,978	$ 6,833
Unrecognized stock-based compensation expense			$ 14,300			$ 14,300
Unrecognized stock-based compensation, expected to be recognized, weighted average period						2 years 7 months 6 days
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of offerings per year | Offering			2			2
Common stock reserved for future issuance | shares			1,000,000			1,000,000
Amount withheld from employees			$ 500		$ 800
Employee stock purchase plan, shares purchased | shares					20,243
Maximum [Member] | Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase price as a percentage of fair market value						85.00%
Equity Incentive Plan [Member] | 2010 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares reserved for issuance under the plan | shares								1,027,620
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 677	943		$ 2,670	2,817
Vesting period						4 years
Stock options exercisable | shares			594,300			594,300
Weighted average exercise price | $ / shares			$ 48.92			$ 48.92
Weighted average remaining contractual life						3 years 3 months 18 days
Weighted average fair value per share of options granted | $ / shares						$ 19.48
Stock Options [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options contractual term range						7 years
Stock Options [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options contractual term range						10 years
Performance Share Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years	3 years
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 1,976	1,173		$ 4,727	3,334
Vesting period						4 years
Number of RSU's vested and not issued during the period | shares						38,321
Restricted Stock Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			137	$ 79		$ 352	$ 238
Restricted stock awards units vest over, period						1 year
401(k) Stock Match [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 293			$ 937
Maximum allowable contribution by employee percentage						100.00%
Defined contribution plan employer matching contribution percent						50.00%
Maximum annual contribution per employee, percent						6.00%

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 3,266	$ 2,347	$ 9,978	$ 6,833
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	677	943	2,670	2,817
Performance Share Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense (reversal of expense)	74		960
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	1,976	1,173	4,727	3,334
Restricted Stock Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	137	79	352	238
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	109	152	332	444
401(k) Stock Match [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	293		937
Cost of Revenues [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	535	494	1,587	1,414
Sales and Marketing [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	691	565	2,054	1,656
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	287	241	973	698
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 1,753	$ 1,047	$ 5,364	$ 3,065

Stock-Based Compensation - St_2

Stock-Based Compensation - Stock Option Activity (Detail)	9 Months Ended
	Sep. 30, 2018$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options Outstanding, Beginning balance | shares	1,097,331
Options, Granted | shares	181,472
Options, Exercised | shares	(286,237)
Options, Forfeited | shares	(60,270)
Options Outstanding, Ending balance | shares	932,296
Weighted Average Exercise Price, Outstanding, Beginning Balance | $ / shares	$ 47.60
Weighted Average Exercise Price, Granted | $ / shares	59.88
Weighted Average Exercise Price, Exercised | $ / shares	41.23
Weighted Average Exercise Price, Forfeited | $ / shares	56.71
Weighted Average Exercise Price, Outstanding, Ending Balance | $ / shares	$ 51.35

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted Average Grant Date Fair Value of Options Granted, Assumptions (Detail) - Stock Options [Member]	9 Months Ended
	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility	34.90%
Dividend yield	0.00%
Life (in years)	4 years 4 months 24 days
Risk-free interest rate	2.53%

Stock-Based Compensation - Perf

Stock-Based Compensation - Performance Share Units and Restricted Stock Units (Detail) - Performance Share Units and Restricted Stock Units [Member]	9 Months Ended
	Sep. 30, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards, Outstanding, Beginning Balance | shares	321,912
Granted, stock units | shares	156,933
Vested, stock units | shares	(81,427)
Forfeited, stock units | shares	(34,318)
Stock awards, Outstanding, Ending Balance | shares	363,100
Weighted average grant date fair value, Outstanding, Beginning Balance | $ / shares	$ 55.16
Granted, Weighted Average Grant Date Fair Value | $ / shares	63.09
Vested, Weighted Average Grant Date Fair Value | $ / shares	56.32
Forfeited, Weighted Average Grant Date Fair Value | $ / shares	54.91
Weighted average grant date fair value, Outstanding, Ending Balance | $ / shares	$ 58.35

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Awards (Detail) - Restricted Stock Award [Member]	9 Months Ended
	Sep. 30, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards, Outstanding, Beginning Balance | shares	1,368
Restricted common stock issued, stock awards | shares	7,304
Restrictions lapsed, stock awards | shares	(5,016)
Forfeited, stock awards | shares	0
Stock awards, Outstanding, Ending Balance | shares	3,656
Weighted average grant date fair value, Outstanding, Beginning Balance | $ / shares	$ 58.29
Restricted common stock issued, Weighted Average Grant Date Fair Value | $ / shares	74.43
Restrictions lapsed, Weighted Average Grant Date Fair Value | $ / shares	70.03
Forfeited, Weighted Average Grant Date Fair Value | $ / shares	0
Weighted average grant date fair value, Outstanding, Ending Balance | $ / shares	$ 74.43

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value Estimation of Common Stock Using Black-Scholes Option Pricing Model, Assumptions (Detail) - Employee Stock Purchase Plan [Member]	9 Months Ended
	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility	26.50%
Dividend yield	0.00%
Life (in years)	6 months
Risk-free interest rate	1.50%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018USD ($)
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 0
Accrued interest or tax penalties	$ 0
Corporate federal income tax rate	21.00%

Net Income Per Share - Componen

Net Income Per Share - Components of Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator
Net income	$ 8,061	$ 2,176	$ 16,731	$ 7,129
Denominator
Weighted average common shares outstanding, basic	17,219	17,223	17,167	17,192
Options to purchase common stock	395	152	293	169
Restricted stock units	127	35	97	33
Weighted average common shares outstanding, diluted	17,741	17,410	17,557	17,394
Net income per share
Basic	$ 0.47	$ 0.13	$ 0.97	$ 0.42
Diluted	$ 0.45	$ 0.13	$ 0.95	$ 0.41
Antidilutive shares (in thousands)		267	27	267