Medidata Solutions 10-Q 1 Aug 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Jul. 25, 2017
Document and Entity Information [Abstract]
Entity registrant name	Medidata Solutions, Inc.
Entity central index key	1,453,814
Document type	10-Q
Amendment flag	false
Document period end date	Jun. 30, 2017
Document fiscal period focus	Q2
Document fiscal year focus	2,017
Current fiscal year end date	--12-31
Entity filer category	Large Accelerated Filer
Entity common stock, shares outstanding		58,504,326

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 110,708	$ 93,519
Marketable securities	256,401	281,285
Accounts receivable, net of allowance for doubtful accounts	111,233	115,216
Prepaid commission expense	3,511	1,842
Prepaid expenses and other current assets	30,846	20,382
Deferred income taxes	0	6,536
Total current assets	512,699	518,780
Restricted cash	5,513	5,760
Furniture, fixtures and equipment, net	71,162	58,461
Marketable securities- long-term	167,896	140,418
Goodwill	47,678	30,780
Intangible assets, net	20,014	5,090
Deferred income taxes- long-term	41,268	40,415
Other assets	22,625	18,181
Total assets	888,855	817,885
Current liabilities:
Accounts payable	12,257	6,202
Accrued payroll and other compensation	19,630	29,260
Accrued expenses and other	34,120	20,958
Deferred revenue	86,314	75,911
Total current liabilities	152,321	132,331
Noncurrent liabilities:
1.00% convertible senior notes, net	270,647	263,401
Deferred revenue, less current portion	2,159	1,703
Deferred tax liabilities	124	322
Other long-term liabilities	20,812	18,138
Total noncurrent liabilities	293,742	283,564
Total liabilities	446,063	415,895
Commitments and contingencies
Stockholders' equity:
Preferred stock	0	0
Common stock	626	614
Additional paid-in capital	454,856	418,497
Treasury stock	(128,991)	(114,204)
Accumulated other comprehensive loss	(3,826)	(5,276)
Retained earnings	120,127	102,359
Total stockholders' equity	442,792	401,990
Total liabilities and stockholders' equity	$ 888,855	$ 817,885

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accounts receivable, allowance for doubtful accounts	$ 1,298	$ 1,041
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000	5,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000	200,000
Common stock, shares issued	62,578	61,393
Common stock, shares outstanding	58,503	57,733
Treasury stock, shares	4,075	3,660

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016		Jun. 30, 2017	Jun. 30, 2016
Revenues
Subscription revenue		$ 114,291	$ 96,760		$ 221,361	$ 186,728
Professional services		23,123	17,850		42,874	32,120
Total revenues		137,414	114,610		264,235	218,848
Cost of revenues
Subscription		17,017	15,600		34,146	29,929
Professional services		14,903	13,457		28,388	23,796
Total cost of revenues	[1],[2]	31,920	29,057		62,534	53,725
Gross profit		105,494	85,553		201,701	165,123
Operating costs and expenses:
Research and development	[2]	35,884	28,267		65,821	56,495
Sales and marketing	[1],[2]	32,784	27,609		62,893	53,067
General and administrative	[2]	23,083	18,531		47,071	37,777
Total operating costs and expenses		91,751	74,407		175,785	147,339
Operating income		13,743	11,146		25,916	17,784
Interest and other income (expense):
Interest expense		(4,383)	(4,183)		(8,710)	(8,310)
Interest income		1,328	932		2,499	1,804
Other income (expense), net		0	3		0	(1)
Total interest and other expense, net		(3,055)	(3,248)		(6,211)	(6,507)
Income before income taxes		10,688	7,898		19,705	11,277
Provision for income taxes		2,438	1,688	[3]	1,937	492	[3]
Net income		$ 8,250	$ 6,210	[3]	$ 17,768	$ 10,785	[3]
Earnings per share:
Basic		$ 0.15	$ 0.11	[3]	$ 0.32	$ 0.20	[3]
Diluted		$ 0.14	$ 0.11	[3]	$ 0.30	$ 0.19	[3]
Weighted average common shares outstanding:
Basic		56,433	55,392		56,254	55,255
Diluted		59,835	56,875	[3]	59,051	56,813	[3]
Total stock-based compensation	[2]	$ 12,692	$ 10,447		$ 23,013	$ 20,697
Total amortization of intangible assets	[1]	1,141	399		1,678	502
Cost of revenues
Weighted average common shares outstanding:
Total stock-based compensation	[2]	1,246	1,239		2,415	2,449
Total amortization of intangible assets	[1]	1,022	314		1,476	393
Research and development
Weighted average common shares outstanding:
Total stock-based compensation	[2]	3,427	2,323		6,262	4,517
Sales and marketing
Weighted average common shares outstanding:
Total stock-based compensation	[2]	1,836	1,839		3,011	3,716
Total amortization of intangible assets	[1]	119	85		202	109
General and administrative
Weighted average common shares outstanding:
Total stock-based compensation	[2]	$ 6,183	$ 5,046		$ 11,325	$ 10,015
[1]	Amortization of intangible assets included in cost of revenues and operating costs and expenses
[2]	Stock-based compensation expense included in cost of revenues and operating costs and expenses
[3]	Prior periods recast to reflect the Company's early adoption of Accounting Standards Update No. 2016-09 in the third quarter of 2016

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016		Jun. 30, 2017	Jun. 30, 2016
Net income	$ 8,250	$ 6,210	[1]	$ 17,768	$ 10,785	[1]
Other comprehensive income (loss):
Foreign currency translation adjustments	879	(565)		1,302	(652)
Unrealized gain (loss) on marketable securities	128	399		240	1,707
Other comprehensive income (loss)	1,007	(166)		1,542	1,055
Income tax effect of unrealized gain or loss on marketable securities	(49)	(581)		(92)	(581)
Other comprehensive income (loss), net of tax	958	(747)		1,450	474
Comprehensive income (loss), net of tax	$ 9,208	$ 5,463	[1]	$ 19,218	$ 11,259	[1]
[1]	Prior periods recast to reflect the Company's early adoption of Accounting Standards Update No. 2016-09 in the third quarter of 2016

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net income		$ 17,768	$ 10,785	[1]
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of intangible assets and depreciation		10,065	6,983
Stock-based compensation	[2]	23,013	20,697
Amortization of discounts or premiums on marketable securities		757	1,700
Deferred income taxes		2,535	(1,164)
Amortization of debt issuance costs		639	639
Amortization of debt discount		6,607	6,224
Provision for doubtful accounts		526	508
Loss on fixed asset disposal		(2)	4
Change in fair value of contingent consideration		58	0
Changes in operating assets and liabilities:
Accounts receivable		4,058	(7,729)
Prepaid commission expense		(4,661)	(2,931)
Prepaid expenses and other current assets		(13,031)	3,040
Other assets		1,171	(3,583)
Accounts payable		4,490	(1,932)
Accrued payroll and other compensation		(10,122)	(4,302)
Accrued expenses and other		5,313	7,715
Deferred revenue		10,634	9,206
Other long-term liabilities		884	(2,814)
Net cash provided by (used in) operating activities		60,702	43,046	[3]
Cash flows from investing activities:
Purchases of furniture, fixtures and equipment		(16,642)	(13,425)
Purchases of available-for-sale securities		(157,228)	(144,136)
Proceeds from sale of available-for-sale securities		154,117	154,784
Acquisition of business, net of cash acquired		(22,941)	(17,142)
Net cash provided by (used in) investing activities		(42,694)	(19,919)	[4]
Cash flows from financing activities:
Proceeds from exercise of stock options		9,057	1,691
Proceeds from employee stock purchase plan		4,248	3,385
Repayments of notes payable		0	(100)
Acquisition of treasury stock		(14,785)	(13,797)
Net cash provided by (used in) financing activities		(1,480)	(8,821)	[3]
Effect of exchange rate on cash, cash equivalents, and restricted cash		414	397
Net increase (decrease) in cash, cash equivalents, and restricted cash		16,942	14,703
Cash, cash equivalents and restricted cash - Beginning of period		99,279	55,472	[4]
Cash, cash equivalents and restricted cash - End of period		116,221	70,175	[4]
Supplemental disclosures of cash flow information:
Interest paid		1,441	1,445
Income taxes paid		2,877	845
Noncash activities:
Furniture, fixtures, and equipment acquired but not yet paid for at period-end		4,671	1,097
Contingent consideration associated with acquisition		$ 5,697	$ 0
[1]	Prior periods recast to reflect the Company's early adoption of Accounting Standards Update No. 2016-09 in the third quarter of 2016
[2]	Stock-based compensation expense included in cost of revenues and operating costs and expenses
[3]	As a result of the Company's early adoption of Accounting Standards Update No. 2016-09 in the third quarter of 2016, the consolidated statement of cash flows for the six months ended June 30, 2016 has been adjusted to reflect an offsetting increase of $5,048 thousand to net cash provided by operating activities and net cash used in financing activities.
[4]	As a result of the Company's early adoption of ASU No. 2016-18 during the first quarter of 2017, the consolidated statement of cash flows for the six months ended June 30, 2016 has been adjusted to include restricted cash in beginning- and end-of-period cash, and to remove change in restricted cash as a reconciling item.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Medidata Solutions, Inc., together with its consolidated subsidiaries (collectively, the "Company"), is the leading global provider of cloud-based solutions for clinical research in life sciences, offering platform technology that transforms clinical development and increases the value of its customers' research investments. The Company was organized as a New York corporation in June 1999 and reincorporated as a Delaware corporation in May 2000. Except to the extent updated or described below, the Company’s significant accounting policies as of June 30, 2017 are the same as those at December 31, 2016 , which are included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2016 , filed with the Securities and Exchange Commission (“SEC”) on February 28, 2017 . Basis of Presentation — The accompanying interim condensed consolidated balance sheets as of June 30, 2017 and December 31, 2016 , the condensed consolidated statements of operations for the three and six months ended June 30, 2017 and 2016 , the condensed consolidated statements of comprehensive income for the three and six months ended June 30, 2017 and 2016 , and the condensed consolidated statements of cash flows for the six months ended June 30, 2017 and 2016 are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and applicable rules and regulations of the SEC for interim financial reporting. Accordingly, certain information and footnote disclosures have been condensed or omitted pursuant to SEC rules that would ordinarily be required by U.S. GAAP for complete financial statements. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and accompanying notes thereto for the fiscal year ended December 31, 2016 included in the Company’s Annual Report on Form 10-K filed with the SEC on February 28, 2017 . The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and, in the opinion of management, reflect all adjustments consisting of normal recurring accruals considered necessary to present fairly the Company’s financial position as of June 30, 2017 , results of its operations for the three and six months ended June 30, 2017 and 2016 , comprehensive income for the three and six months ended June 30, 2017 and 2016 , and cash flows for the six months ended June 30, 2017 and 2016 . The results of operations for the three and six months ended June 30, 2017 are not necessarily indicative of the results that may be expected for the year ending December 31, 2017 . Income Taxes — The Company’s interim period provision for income taxes is computed by using an estimate of the annual effective tax rate, adjusted for discrete items taken into account in the relevant period, if any. Each quarter, the annual effective income tax rate is recomputed and if there are material changes in the estimate, a cumulative adjustment is made. Accounts Receivable — Accounts receivable are recorded at original invoice amount less an allowance that management believes will be adequate to absorb estimated losses on uncollectible accounts. This allowance is based on an evaluation of the collectability of accounts receivable and prior bad debt experience. Accounts receivable are written off when deemed uncollectible. Unbilled receivables consist of revenue recognized in excess of billings, substantially all of which is expected to be billed and collected within one year. As of June 30, 2017 and December 31, 2016 , unbilled accounts receivable of $12.5 million and $14.1 million , respectively, were included in accounts receivable on the Company's consolidated balance sheets. In general, there is a direct relationship between the Company's accounts receivable balance and its transaction volume. Recently Adopted Accounting Pronouncements — In November 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2015-17, Income Taxes: Balance Sheet Classification of Deferred Taxes , which simplifies the presentation of deferred income taxes by requiring that all deferred tax assets and liabilities be classified as noncurrent in the consolidated balance sheets. ASU No. 2015-17 is effective for annual reporting periods beginning after December 15, 2016 and interim periods within those annual periods, and may be applied either prospectively or retrospectively to all periods presented. The Company adopted ASU No. 2015-17 prospectively on January 1, 2017, and the adoption did not have a material impact on its consolidated financial statements, aside from a balance sheet reclassification from short-term to long-term deferred income taxes. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes: Intra-Entity Transfers of Assets Other Than Inventory, which requires entities to recognize the income tax consequences of intra-entity transfers of assets other than inventory when those transfers occur. ASU No. 2016-16 is effective for annual reporting periods beginning after December 15, 2017, including interim periods within those annual periods. The Company early adopted ASU No. 2016-16 on January 1, 2017, and the adoption had no impact on its consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows: Restricted Cash , which requires entities to include restricted cash in cash and cash equivalents when reconciling beginning-of-period and end-of-period cash in the statement of cash flows. ASU No. 2016-18 is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. The Company early adopted ASU No. 2016-18 retrospectively on January 1, 2017 and the adoption did not have a material impact on its consolidated financial statements, aside from changes in presentation. Recently Issued Accounting Pronouncements — There have been no changes in the expected dates of adoption or estimated effects on the Company's consolidated financial statements of recently issued accounting pronouncements from those disclosed in the Company’s Annual Report on Form 10-K, except as described below. ASU No. 2014-09, Revenue from Contracts with Customers , which creates Accounting Standards Codification ("ASC") 606 and supersedes the existing accounting standards for revenue recognition in ASC 605, provides principles for recognizing revenue 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 and services. ASU No. 2014-09 is effective for annual reporting periods beginning after December 15, 2017, including interim periods within those annual periods. The Company will adopt ASU No. 2014-09 on January 1, 2018. The Company's assessment of the impact of this updated standard is ongoing; however, the Company continues to expect to identify performance obligations under the new guidance in ASC 606 that are similar to the deliverables and separate units of account identified under the current guidance ASC 605. As a result, the Company anticipates that timing of revenue recognition for most of its contracts will remain the same. A few of the Company's contracts include contingent amounts of variable consideration that were precluded from recognition because of the requirement for amounts to be “fixed or determinable” under ASC 605-10-S99. However, the Company anticipates that ASC 606 will require it to estimate these amounts in advance. As a result, the Company expects to recognize revenue from these contracts earlier under ASC 606 than under ASC 605. ASU No. 2014-09 also creates a new subtopic under ASC 340, Other Assets and Deferred Costs , which discusses the deferral of incremental costs of obtaining a contract with a customer, including the period of amortization of such costs. The Company is still evaluating the planned amortization period for such costs, but expects a longer amortization period than under the current guidance. The Company plans to choose between the permitted full and modified retrospective transition methods at the conclusion of its evaluation in the second half of 2017. In May 2017, the FASB issued ASU No. 2017-09, Scope of Modification Accounting, which clarifies when a change in the terms or conditions of a share-based payment award should be accounted for as a modification. ASU No. 2017-09 is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. The Company will adopt ASU No. 2017-09 on January 1, 2018, and the adoption is not expected to have a material impact on its consolidated financial statements.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
STOCKHOLDERS' EQUITY	STOCKHOLDERS' EQUITY Common Stock — Common stockholders are entitled to one vote for each share of common stock held. Common stockholders may receive dividends if and when the board of directors determines, at its sole discretion. Treasury Stock — From time to time, the Company grants nonvested restricted stock awards ("RSAs"), restricted stock units ("RSUs"), and performance-based restricted stock units ("PBRSUs") to its employees pursuant to the terms of its 2017 Long-Term Incentive Plan ("2017 Plan") and formerly pursuant to the terms of its Second Amended and Restated 2009 Long-Term Incentive Plan ("2009 Plan"). Under the provisions of the 2017 Plan and 2009 Plan, unless otherwise elected, participants fulfill their related income tax withholding obligation by having shares withheld at the time of vesting. On the date of vesting, the Company divides the participant's income tax withholding obligation in dollars by the closing price of its common stock and withholds the resulting number of vested shares. The shares withheld are then transferred to the Company's treasury stock at cost. During the six months ended June 30, 2017 and 2016 , the Company withheld 260,737 shares at an average price of $56.71 and 326,568 shares at an average price of $35.59 , respectively, in connection with the vesting of equity awards. Nonvested restricted stock awards forfeited by plan participants are transferred to the Company's treasury stock at par. During the six months ended June 30, 2017 and 2016 , 154,106 and 99,876 forfeited shares, respectively, were transferred to treasury stock at their par value of $0.01 .

Investments

Investments	6 Months Ended
	Jun. 30, 2017
Investments [Abstract]
INVESTMENTS	INVESTMENTS Marketable Securities Marketable securities, which the Company classifies as available-for-sale securities, primarily consist of high quality commercial paper, corporate bonds, and U.S. government debt obligations. Marketable securities with remaining effective maturities of twelve months or less from the balance sheet date are classified as short-term; otherwise, they are classified as long-term on the consolidated balance sheets. The following tables provide the Company’s marketable securities by security type as of June 30, 2017 and December 31, 2016 (in thousands): As of June 30, 2017 Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Commercial paper and corporate bonds $ 390,313 $ 16 $ (594 ) $ 389,735 U.S. government agency debt securities 34,631 — (69 ) 34,562 Total $ 424,944 $ 16 $ (663 ) $ 424,297 As of December 31, 2016 Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Commercial paper and corporate bonds $ 389,459 $ 4 $ (827 ) $ 388,636 U.S. government agency debt securities 33,132 — (65 ) 33,067 Total $ 422,591 $ 4 $ (892 ) $ 421,703 Contractual maturities of the Company’s marketable securities as of June 30, 2017 and December 31, 2016 are summarized as follows (in thousands): As of June 30, 2017 As of December 31, 2016 Cost Estimated Fair Value Cost Estimated Fair Value Due in one year or less $ 256,720 $ 256,401 $ 281,591 $ 281,285 Due in one to five years 168,224 167,896 141,000 140,418 Total $ 424,944 $ 424,297 $ 422,591 $ 421,703 At June 30, 2017 , the Company had $0.7 million of gross unrealized losses primarily due to a decrease in the fair value of certain corporate bonds. The Company regularly reviews its investment portfolio to identify and evaluate investments that have indications of possible impairment. Investments that are impaired are those that are considered to have losses that are other-than-temporary. Factors considered in determining whether a loss is temporary include: • the length of time and extent to which fair value has been lower than the cost basis; • the financial condition, credit quality and near-term prospects of the investee; and • whether it is more likely than not that the Company will be required to sell the security prior to recovery. As the Company has the ability and intent to hold these investments until a recovery of fair value, which may be maturity, the Company has determined that the gross unrealized losses on such investments at June 30, 2017 are temporary in nature. Accordingly, the Company did not consider its investments in marketable securities to be other-than-temporarily impaired as of June 30, 2017 . The following tables provide the fair market value and gross unrealized losses of the Company's marketable securities with unrealized losses, aggregated by security type, as of June 30, 2017 and December 31, 2016 (in thousands): In Loss Position for Less than 12 Months As of June 30, 2017 As of December 31, 2016 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Commercial paper and corporate bonds $ 347,730 $ (549 ) $ 299,708 $ (771 ) U.S. government agency debt securities 22,776 (54 ) 28,273 (59 ) Total $ 370,506 $ (603 ) $ 327,981 $ (830 ) In Loss Position for More than 12 Months As of June 30, 2017 As of December 31, 2016 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Commercial paper and corporate bonds $ 25,200 $ (45 ) $ 68,158 $ (56 ) U.S. government agency debt securities 11,785 (15 ) 4,794 (6 ) Total $ 36,985 $ (60 ) $ 72,952 $ (62 ) During the three and six months ended June 30, 2017 and 2016 , the Company recorded an insignificant amount of net realized gains from the sale of marketable securities. Cost Method Investment The Company holds shares of Series B Preferred Stock of SHYFT Analytics, Inc. ("SHYFT"), purchased via a private placement. This investment is accounted for under the cost method and is included in other assets on the Company's consolidated balance sheet as of June 30, 2017 at its purchase price of $4.0 million .

Fair Value

Fair Value	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
FAIR VALUE	FAIR VALUE The following table summarizes, as of June 30, 2017 and December 31, 2016 , the Company's financial assets and liabilities that are measured at fair value on a recurring basis, according to the fair value hierarchy described in the significant accounting policies included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2016 (in thousands): As of June 30, 2017 As of December 31, 2016 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Cash $ 110,632 $ — $ — $ 110,632 $ 93,384 $ — $ — $ 93,384 Money market funds 76 — — 76 135 — — 135 Total cash and cash equivalents 110,708 — — 110,708 93,519 — — 93,519 Commercial paper and corporate bonds — 389,735 — 389,735 — 388,636 — 388,636 U.S. government agency debt securities — 34,562 — 34,562 — 33,067 — 33,067 Total marketable securities — 424,297 — 424,297 — 421,703 — 421,703 Total financial assets measured at fair value on a recurring basis $ 110,708 $ 424,297 $ — $ 535,005 $ 93,519 $ 421,703 $ — $ 515,222 Contingent consideration – short-term $ — $ — $ 3,965 $ 3,965 $ — $ — $ — $ — Contingent consideration – long-term — — 1,790 1,790 — — — — Total financial liabilities measured at fair value on a recurring basis $ — $ — $ 5,755 $ 5,755 $ — $ — $ — $ — Investments in commercial paper, corporate bonds, and U.S. government agency debt securities have been classified as Level 2 as they are valued using quoted prices in less active markets or other directly or indirectly observable inputs. Fair values of corporate bonds and U.S. government agency debt securities were derived from a consensus or weighted-average price based on input of market prices from multiple sources at each reporting period. With regard to commercial paper, all of the securities had high credit ratings and one year or less to maturity; therefore, fair value was derived from accretion of purchase price to face value over the term of maturity or quoted market prices for similar instruments if available. During the six months ended June 30, 2017 and 2016 , there were no transfers of financial assets between Level 1 and Level 2. Contingent consideration liabilities associated with acquisition-related earn-out payments are classified as Level 3 in the fair value hierarchy because they rely significantly on inputs that are unobservable in the market. The fair value of short-term contingent consideration, which is related to the achievement of a technical milestone, has been estimated using situation-based modeling, which considers the probability-weighted present value of the expected payout amount. Significant assumptions include the Company's expectations with regard to the likelihood and timing of achievement of the related technical milestone and a discount rate of 2.9%. The fair value of long-term contingent consideration, which is related to achievement of revenue targets, has been estimated using a Monte Carlo simulation to simulate future performance of the acquired business under a risk-neutral framework; significant assumptions include a risk-adjusted discount rate of 10.2% and revenue volatility of 8.0%. Short-term and long-term contingent consideration are recorded in accrued expenses and other and other long-term liabilities, respectively, on the Company's consolidated balance sheet as of June 30, 2017 . The following table provides a summary of changes in fair value of the Company's Level 3 financial liabilities during the six months ended June 30, 2017 (in thousands): Balance as of January 1, 2017 $ — Contingent consideration — acquisition 5,697 Fair value adjustment (included in general and administrative expenses) 58 Balance as of June 30, 2017 $ 5,755 The carrying amounts of all other current financial assets and current financial liabilities reflected in the consolidated balance sheets approximate fair value due to their short-term nature.

Acquisitions

Acquisitions	6 Months Ended
	Jun. 30, 2017
Business Combinations [Abstract]
ACQUISITION	ACQUISITIONS The Company acquired all outstanding equity interests in CHITA Inc. ("CHITA") and Mytrus, Incorporated ("Mytrus") on February 17, 2017 and April 18, 2017 , respectively. CHITA provides regulated content management for the life sciences industry. Mytrus provides cloud-based software for electronic informed consent ("eConsent"), which replaces paper patient consent forms. Through these acquisitions, the Company adds regulated document and standard operating procedure ("SOP") management, electronic trial master file ("eTMF"), and eConsent capabilities to its platform. Aggregate purchase consideration of $28.9 million consisted of upfront consideration of $23.2 million and contingent consideration (associated with CHITA) initially valued at $5.7 million . In connection with these acquisitions, the Company recognized $16.6 million in finite-lived intangible assets, deferred tax liabilities of $2.9 million , and $1.5 million in other net tangible liabilities, resulting in the recognition of $16.7 million in goodwill. Intangible assets acquired were as follows (in thousands): Acquisition Date Fair Value Weighted-Average Useful Life Developed technology $ 15,602 5 years Customer relationships 890 6 years Non-competition agreements 110 3.5 years Total $ 16,602 The Company does not consider these acquisitions, individually or in the aggregate, to be significant to its financial condition or results of operations; its consolidated results of operations for the three and six months ended June 30, 2017 include the revenues and expenses of CHITA and Mytrus since their respective acquisition dates.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	6 Months Ended
	Jun. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND INTANGIBLE ASSETS	GOODWILL AND INTANGIBLE ASSETS The change in the carrying amount of goodwill during the six months ended June 30, 2017 was as follows (in thousands): Balance as of January 1, 2017 $ 30,780 Additions related to acquisitions 16,690 Foreign currency translation adjustments 208 Balance as of June 30, 2017 $ 47,678 Total intangible assets are summarized as follows (in thousands): As of June 30, 2017 As of December 31, 2016 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Developed technology $ 24,386 $ (6,644 ) $ 17,742 $ 8,714 $ (5,098 ) $ 3,616 Customer relationships 4,475 (2,373 ) 2,102 3,566 (2,176 ) 1,390 Non-competition agreements 260 (90 ) 170 150 (66 ) 84 Total $ 29,121 $ (9,107 ) $ 20,014 $ 12,430 $ (7,340 ) $ 5,090 Future amortization of intangible assets is expected to be as follows (in thousands): Remainder of year ending December 31, 2017 $ 2,427 Years ending December 31, 2018 4,788 2019 4,530 2020 3,787 2021 3,517 2022 921 Thereafter 44 Total $ 20,014

Debt

Debt	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
DEBT	DEBT The Company's 1.00% convertible senior notes (the "Notes"), issued in August 2013, consisted of the following components as of June 30, 2017 and December 31, 2016 (in thousands): June 30, December 31, Equity component, net of equity issue costs $ 60,222 $ 60,222 Liability component: Principal 287,500 287,500 Less: unamortized debt discount (15,469 ) (22,076 ) Less: unamortized debt issuance costs (1,384 ) (2,023 ) Net carrying amount $ 270,647 $ 263,401 As of June 30, 2017 and December 31, 2016 , the estimated fair value of the Notes was $398.6 million and $314.4 million , respectively. The Company considers this disclosure to be a Level 2 measurement because it is based upon a recent modeled bid-price quote for the Notes, reflecting activity in a less active market. Based on the closing price of the Company's common stock as of June 30, 2017 of $78.20 , which is higher than the Notes' initial conversion price of $58.05 , the if-converted value of the Notes exceeded their face value by $99.8 million. As of June 30, 2017 , the remaining life of the Notes is approximately 13 months . The following table sets forth total interest expense recognized related to the Notes for the three and six months ended June 30, 2017 and 2016 (in thousands except percentages): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Contractual interest expense $ 719 $ 719 $ 1,438 $ 1,438 Amortization of debt issuance costs 320 320 639 639 Amortization of debt discount 3,328 3,135 6,607 6,224 Total $ 4,367 $ 4,174 $ 8,684 $ 8,301 Effective interest rate 6.5 % 6.5 % 6.5 % 6.5 %

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION For the three and six months ended June 30, 2017 and 2016 , the components of stock-based compensation expense were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Stock options $ 938 $ 998 $ 1,855 $ 2,053 Restricted stock awards and units 7,769 6,263 14,688 11,741 Performance-based restricted stock units 3,074 2,235 4,702 4,869 Employee stock purchase plan 969 951 1,897 2,034 Total stock-based compensation (1) $ 12,750 $ 10,447 $ 23,142 $ 20,697 (1) Total stock-based compensation is presented in this table on a gross basis, consistent with the additional paid-in capital impact recorded in stockholders' equity. On the Company's consolidated statements of operations and consolidated statements of cash flows, stock-based compensation is presented net of foreign exchange impact and capitalization of eligible software development-related costs. Stock Options The fair value of each stock option granted during the three and six months ended June 30, 2017 and 2016 was estimated on the date of grant using a Black-Scholes pricing model with the following weighted-average assumptions: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Expected volatility 43 % 44 % 44 % 43 % Expected life 6 years 6 years 6 years 6 years Risk-free interest rate 2.02 % 1.40 % 2.07 % 1.45 % Dividend yield — — — — The following table summarizes the status of the Company's stock options as of June 30, 2017 , and changes during the six months then ended (in thousands, except per share data): Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (years) Aggregate Intrinsic Value Outstanding at January 1, 2017 1,793 $23.39 Granted 77 56.90 Exercised (268 ) 33.81 Forfeited (42 ) 44.08 Expired (7 ) 58.92 Outstanding at June 30, 2017 1,553 $22.53 4.70 $86,484 Exercisable at June 30, 2017 1,249 $16.18 3.76 $77,450 Vested and expected to vest at June 30, 2017 1,521 $21.97 4.61 $85,499 The weighted-average grant-date fair value of stock options granted during the three months ended June 30, 2017 and 2016 was $25.47 and $17.34 , respectively. The weighted-average grant-date fair value of stock options granted during the six months ended June 30, 2017 and 2016 was $25.37 and $17.14 , respectively. The total intrinsic value of stock options exercised during the three months ended June 30, 2017 and 2016 was $4.0 million and $2.3 million , respectively. The total intrinsic value of stock options exercised during the six months ended June 30, 2017 and 2016 was $8.0 million and $3.0 million , respectively. The total fair value of stock options vested during the three months ended June 30, 2017 and 2016 was $1.0 million and $1.3 million , respectively. The total fair value of stock options vested during the six months ended June 30, 2017 and 2016 was $2.1 million and $2.1 million , respectively. As of June 30, 2017 , there was $5.9 million in unrecognized compensation cost related to all non-vested stock options granted. This cost is expected to be recognized over a weighted-average remaining period of 2.58 years . R estricted Stock Awards and Units The following table summarizes the status of the Company’s nonvested time-based RSAs and RSUs as of June 30, 2017 , and changes during the six months then ended (in thousands, except per share data): Number of Shares Weighted- Average Grant Date Fair Value Nonvested at January 1, 2017 1,850 $40.89 Granted 727 56.91 Vested (537 ) 38.77 Forfeited (156 ) 41.40 Nonvested at June 30, 2017 1,884 $47.66 The total fair value of RSAs and RSUs vested during the three months ended June 30, 2017 and 2016 was $4.7 million and $7.5 million , respectively. The total fair value of RSAs and RSUs vested during the six months ended June 30, 2017 and 2016 was $31.0 million and $16.9 million , respectively. As of June 30, 2017 , there was $76.7 million in unrecognized compensation cost related to all nonvested RSAs and RSUs granted. This cost is expected to be recognized over a weighted-average remaining period of 2.76 years . Performance-Based Restricted Stock Units No PBRSUs were granted during the three months ended June 30, 2017 and 2016 . During the six months ended June 30, 2017 , the Company granted: (1) 132 thousand PBRSUs ("2017 TSR PBRSUs") with market conditions based on the Company's total stockholder return ("TSR") relative to that of the Russell 2000 Index over the three-year period ending December 31, 2019, vesting in full in three years with the number of shares ultimately earned ranging from zero to 200% of the target number of shares ; (2) 132 thousand PBRSUs ("2017 Net Income PBRSUs") with performance conditions based on the compound annual growth rate of net income over the three-year period ending December 31, 2019, vesting in full in three years with the number of shares ultimately earned ranging from zero to 200% of the target number of shares. During the six months ended June 30, 2016 , the Company granted 223 thousand PBRSUs ("2016 TSR PBRSUs") with market conditions based on the Company's TSR relative to that of the Russell 2000 Index over the three-year period ending December 31, 2018, vesting in full in three years with the number of shares ultimately earned ranging from zero to 200% of the target number of shares . The Company also granted an insignificant number of other PBRSUs with performance conditions based on achievement of certain individual performance objectives. The fair value of PBRSUs with market conditions granted during the six months ended June 30, 2017 and 2016 was estimated as of the date of grant using a Monte Carlo valuation model with the following weighted average assumptions: 2017 TSR PBRSUs 2016 TSR PBRSUs Expected volatility - Medidata 42 % 48 % Expected volatility - comparison index 43 % 43 % Expected life 2.85 years 2.84 years Risk-free interest rate 1.40 % 0.91 % Dividend yield — — The following table summarizes the status of the Company’s PBRSUs based upon expected performance as of June 30, 2017 , and changes during the six months then ended (in thousands, except per share data): Net Income TSR Other Total Number of Shares Weighted-Average Grant Date Fair Value Nonvested at January 1, 2017 — 390 2 392 $ 57.05 Granted (based on performance at 100% of targeted levels) 132 132 — 264 71.51 Adjustment related to expected performance 66 402 — 468 61.82 Vested — (92 ) — (92 ) 67.30 Forfeited — (26 ) — (26 ) 59.60 Nonvested at June 30, 2017 198 806 2 1,006 $ 62.06 No PBRSUs vested during the three months ended June 30, 2017 and 2016 . The total fair value of PBRSUs vested during the six months ended June 30, 2017 and 2016 was $5.1 million and $10.0 million , respectively. As of June 30, 2017 , there was $26.4 million in unrecognized compensation cost related to all nonvested PBRSUs. This cost is expected to be recognized over a weighted-average remaining period of 2.00 years . Employee Stock Purchase Plan The fair value of shares granted under the Company's employee stock purchase plan ("ESPP") was estimated using a Black-Scholes pricing model with the following weighted-average assumptions: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Expected volatility 39 % 46 % 39 % 46 % Expected life 1.49 years 1.68 years 1.49 years 1.68 years Risk-free interest rate 0.62 % 0.58 % 0.62 % 0.58 % Dividend yield — — — — During the three and six months ended June 30, 2017 , 103 thousand shares were purchased under the ESPP at a weighted-average price of $40.50 . During the three and six months ended June 30, 2016 , 89 thousand shares were purchased under the ESPP at a weighted-average price of $38.35 . As of June 30, 2017 , there was $3.4 million in unrecognized compensation cost related to ESPP shares. This cost is expected to be recognized over a weighted-average remaining period of 1.04 years . Modifications Incremental expense associated with modifications to stock options, RSAs and PBRSUs during the three months ended June 30, 2017 and 2016 was none and $0.1 million in the aggregate, respectively and immaterial on an individual basis. Incremental expense during the six months ended June 30, 2017 and 2016 was $0.1 million and $0.3 million in the aggregate, respectively and immaterial on an individual basis.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	6 Months Ended
	Jun. 30, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
ACCUMULATED OTHER COMPREHENSIVE INCOME	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) The changes in the balances of each component of accumulated other comprehensive loss during the six months ended June 30, 2017 were as follows (in thousands): Foreign currency translation adjustments Unrealized gains (losses) on marketable securities Total Balance as of January 1, 2017 $ (4,729 ) $ (547 ) $ (5,276 ) Other comprehensive income 1,302 148 1,450 Balance as of June 30, 2017 $ (3,427 ) $ (399 ) $ (3,826 ) For the six months ended June 30, 2017 and 2016 , reclassifications of items from accumulated other comprehensive income (loss) to net income were insignificant.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE Basic earnings per share is calculated by dividing net income available to common stockholders by the weighted-average number of shares outstanding during the period. The holders of unvested RSAs do not have nonforfeitable rights to dividends or dividend equivalents and therefore, such vested awards do not qualify as participating securities and are excluded from the basic earnings per share calculation. Diluted earnings per share includes the determinants of basic net income per share and, in addition, gives effect to the potential dilution that would occur if securities or other contracts to issue common stock are exercised, vested, or converted into common stock, unless they are anti-dilutive. As the Company intends to settle the principal amount of the Notes (see Note 7 , "Debt") in cash upon conversion, their dilutive effect is reflected in diluted earnings per share using the treasury stock method, which considers the number of shares that would be required to settle any premium above principal at the average stock price for the period. During the three and six months ended June 30, 2016 , the average price of the Company's stock was below the conversion price of the Notes; as a result, the Notes were not dilutive for these periods. A reconciliation of the numerator and denominator of basic earnings per share and diluted earnings per share for the three and six months ended June 30, 2017 and 2016 is shown in the following table (in thousands, except per share data): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 (1) 2017 2016 (1) Numerator Net income $ 8,250 $ 6,210 $ 17,768 $ 10,785 Denominator Denominator for basic earnings per share: Weighted average common shares outstanding 56,433 55,392 56,254 55,255 Denominator for diluted earnings per share: Dilutive potential common shares: Stock options 1,001 980 976 977 Restricted stock awards and units 798 409 835 440 Performance-based restricted stock units 625 94 560 141 Employee stock purchase plan 149 — 114 — Convertible senior notes 829 — 312 — Weighted average common shares outstanding with assumed conversion 59,835 56,875 59,051 56,813 Basic earnings per share $ 0.15 $ 0.11 $ 0.32 $ 0.20 Diluted earnings per share $ 0.14 $ 0.11 $ 0.30 $ 0.19 (1) Prior period recast to reflect the Company's early adoption of ASU No. 2016-09 in the third quarter of 2016. Anti-dilutive common stock equivalents excluded from the calculation of diluted earnings per share for the three and six months ended June 30, 2017 and 2016 are shown in the following table (in thousands, except per share data): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 (1) 2017 2016 (1) Stock options 94 665 202 636 Restricted stock awards and units 1 132 10 121 Performance-based restricted stock units — — — 166 Employee stock purchase plan 275 233 275 233 Total 370 1,030 487 1,156 (1) Prior period recast to reflect the Company's early adoption of ASU No. 2016-09 in the third quarter of 2016.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Company's unrecognized tax benefits were approximately $2.9 million as of June 30, 2017 , and were unchanged from December 31, 2016 .

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Legal Matters — The Company is subject to legal proceedings and claims that arise in the ordinary course of business and records an estimated liability for these matters when an adverse outcome is considered to be probable and can be reasonably estimated. Although the outcome of the litigation cannot be predicted with certainty and some lawsuits, claims, or proceedings may be disposed of unfavorably to the Company, which could materially and adversely affect its financial condition or results of operations, the Company does not believe that it is currently a party to any material legal proceedings. Contractual Warranties — The Company typically provides contractual warranties to its customers covering its solutions and services. To date, any refunds provided to customers have been immaterial. Change in Control Agreements — The Company has change in control agreements with its chief executive officer and certain other executive officers. These agreements provide for payments to be made to such officers upon involuntary termination of their employment by the Company without cause or by such officers for good reason as defined in the agreements, within a period of 2 years following a change in control. The agreements provide that, upon a qualifying termination event, such officers will be entitled to (a) a severance payment equal to the sum of the officer’s base salary and target bonus amount (except that such payment for the Company's chief executive officer and president would be two times such sum); (b) continuation of health benefits for one year (except that such continuation for the Company's chief executive officer and president would be for two years); and (c) immediate vesting of remaining unvested equity awards, unless otherwise specified in the equity award agreements. Wire Transaction Claim — In September 2014, the Company discovered that it had been the victim of a crime involving the fraudulently induced transfer of $4.8 million. The Company filed an insurance claim for its loss, and its insurer, Federal Insurance Co. ("Federal"), denied coverage. The Company commenced legal action, alleging that Federal had wrongly denied coverage. On July 21, 2017, the United States District Court for the Southern District of New York granted the Company's motion for summary judgment, and denied Federal's motion.

Summary of Significant Accoun19

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Basis of presentation	Basis of Presentation — The accompanying interim condensed consolidated balance sheets as of June 30, 2017 and December 31, 2016 , the condensed consolidated statements of operations for the three and six months ended June 30, 2017 and 2016 , the condensed consolidated statements of comprehensive income for the three and six months ended June 30, 2017 and 2016 , and the condensed consolidated statements of cash flows for the six months ended June 30, 2017 and 2016 are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and applicable rules and regulations of the SEC for interim financial reporting. Accordingly, certain information and footnote disclosures have been condensed or omitted pursuant to SEC rules that would ordinarily be required by U.S. GAAP for complete financial statements. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and accompanying notes thereto for the fiscal year ended December 31, 2016 included in the Company’s Annual Report on Form 10-K filed with the SEC on February 28, 2017 . The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and, in the opinion of management, reflect all adjustments consisting of normal recurring accruals considered necessary to present fairly the Company’s financial position as of June 30, 2017 , results of its operations for the three and six months ended June 30, 2017 and 2016 , comprehensive income for the three and six months ended June 30, 2017 and 2016 , and cash flows for the six months ended June 30, 2017 and 2016 . The results of operations for the three and six months ended June 30, 2017 are not necessarily indicative of the results that may be expected for the year ending December 31, 2017 .
Income taxes	Income Taxes — The Company’s interim period provision for income taxes is computed by using an estimate of the annual effective tax rate, adjusted for discrete items taken into account in the relevant period, if any. Each quarter, the annual effective income tax rate is recomputed and if there are material changes in the estimate, a cumulative adjustment is made.
Accounts receivable	Accounts Receivable — Accounts receivable are recorded at original invoice amount less an allowance that management believes will be adequate to absorb estimated losses on uncollectible accounts. This allowance is based on an evaluation of the collectability of accounts receivable and prior bad debt experience. Accounts receivable are written off when deemed uncollectible. Unbilled receivables consist of revenue recognized in excess of billings, substantially all of which is expected to be billed and collected within one year. As of June 30, 2017 and December 31, 2016 , unbilled accounts receivable of $12.5 million and $14.1 million , respectively, were included in accounts receivable on the Company's consolidated balance sheets. In general, there is a direct relationship between the Company's accounts receivable balance and its transaction volume.
Recently issued accounting pronouncements	Recently Adopted Accounting Pronouncements — In November 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2015-17, Income Taxes: Balance Sheet Classification of Deferred Taxes , which simplifies the presentation of deferred income taxes by requiring that all deferred tax assets and liabilities be classified as noncurrent in the consolidated balance sheets. ASU No. 2015-17 is effective for annual reporting periods beginning after December 15, 2016 and interim periods within those annual periods, and may be applied either prospectively or retrospectively to all periods presented. The Company adopted ASU No. 2015-17 prospectively on January 1, 2017, and the adoption did not have a material impact on its consolidated financial statements, aside from a balance sheet reclassification from short-term to long-term deferred income taxes. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes: Intra-Entity Transfers of Assets Other Than Inventory, which requires entities to recognize the income tax consequences of intra-entity transfers of assets other than inventory when those transfers occur. ASU No. 2016-16 is effective for annual reporting periods beginning after December 15, 2017, including interim periods within those annual periods. The Company early adopted ASU No. 2016-16 on January 1, 2017, and the adoption had no impact on its consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows: Restricted Cash , which requires entities to include restricted cash in cash and cash equivalents when reconciling beginning-of-period and end-of-period cash in the statement of cash flows. ASU No. 2016-18 is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. The Company early adopted ASU No. 2016-18 retrospectively on January 1, 2017 and the adoption did not have a material impact on its consolidated financial statements, aside from changes in presentation. Recently Issued Accounting Pronouncements — There have been no changes in the expected dates of adoption or estimated effects on the Company's consolidated financial statements of recently issued accounting pronouncements from those disclosed in the Company’s Annual Report on Form 10-K, except as described below. ASU No. 2014-09, Revenue from Contracts with Customers , which creates Accounting Standards Codification ("ASC") 606 and supersedes the existing accounting standards for revenue recognition in ASC 605, provides principles for recognizing revenue 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 and services. ASU No. 2014-09 is effective for annual reporting periods beginning after December 15, 2017, including interim periods within those annual periods. The Company will adopt ASU No. 2014-09 on January 1, 2018. The Company's assessment of the impact of this updated standard is ongoing; however, the Company continues to expect to identify performance obligations under the new guidance in ASC 606 that are similar to the deliverables and separate units of account identified under the current guidance ASC 605. As a result, the Company anticipates that timing of revenue recognition for most of its contracts will remain the same. A few of the Company's contracts include contingent amounts of variable consideration that were precluded from recognition because of the requirement for amounts to be “fixed or determinable” under ASC 605-10-S99. However, the Company anticipates that ASC 606 will require it to estimate these amounts in advance. As a result, the Company expects to recognize revenue from these contracts earlier under ASC 606 than under ASC 605. ASU No. 2014-09 also creates a new subtopic under ASC 340, Other Assets and Deferred Costs , which discusses the deferral of incremental costs of obtaining a contract with a customer, including the period of amortization of such costs. The Company is still evaluating the planned amortization period for such costs, but expects a longer amortization period than under the current guidance. The Company plans to choose between the permitted full and modified retrospective transition methods at the conclusion of its evaluation in the second half of 2017. In May 2017, the FASB issued ASU No. 2017-09, Scope of Modification Accounting, which clarifies when a change in the terms or conditions of a share-based payment award should be accounted for as a modification. ASU No. 2017-09 is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. The Company will adopt ASU No. 2017-09 on January 1, 2018, and the adoption is not expected to have a material impact on its consolidated financial statements.
Earnings per share	Basic earnings per share is calculated by dividing net income available to common stockholders by the weighted-average number of shares outstanding during the period. The holders of unvested RSAs do not have nonforfeitable rights to dividends or dividend equivalents and therefore, such vested awards do not qualify as participating securities and are excluded from the basic earnings per share calculation. Diluted earnings per share includes the determinants of basic net income per share and, in addition, gives effect to the potential dilution that would occur if securities or other contracts to issue common stock are exercised, vested, or converted into common stock, unless they are anti-dilutive. As the Company intends to settle the principal amount of the Notes (see Note 7 , "Debt") in cash upon conversion, their dilutive effect is reflected in diluted earnings per share using the treasury stock method, which considers the number of shares that would be required to settle any premium above principal at the average stock price for the period. During the three and six months ended June 30, 2016 , the average price of the Company's stock was below the conversion price of the Notes; as a result, the Notes were not dilutive for these periods.

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2017
Investments [Abstract]
Marketable securities by security type	The following tables provide the Company’s marketable securities by security type as of June 30, 2017 and December 31, 2016 (in thousands): As of June 30, 2017 Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Commercial paper and corporate bonds $ 390,313 $ 16 $ (594 ) $ 389,735 U.S. government agency debt securities 34,631 — (69 ) 34,562 Total $ 424,944 $ 16 $ (663 ) $ 424,297 As of December 31, 2016 Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Commercial paper and corporate bonds $ 389,459 $ 4 $ (827 ) $ 388,636 U.S. government agency debt securities 33,132 — (65 ) 33,067 Total $ 422,591 $ 4 $ (892 ) $ 421,703
Contractual maturities of marketable securities	Contractual maturities of the Company’s marketable securities as of June 30, 2017 and December 31, 2016 are summarized as follows (in thousands): As of June 30, 2017 As of December 31, 2016 Cost Estimated Fair Value Cost Estimated Fair Value Due in one year or less $ 256,720 $ 256,401 $ 281,591 $ 281,285 Due in one to five years 168,224 167,896 141,000 140,418 Total $ 424,944 $ 424,297 $ 422,591 $ 421,703
Fair market value and gross unrealized losses of marketable securities	The following tables provide the fair market value and gross unrealized losses of the Company's marketable securities with unrealized losses, aggregated by security type, as of June 30, 2017 and December 31, 2016 (in thousands): In Loss Position for Less than 12 Months As of June 30, 2017 As of December 31, 2016 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Commercial paper and corporate bonds $ 347,730 $ (549 ) $ 299,708 $ (771 ) U.S. government agency debt securities 22,776 (54 ) 28,273 (59 ) Total $ 370,506 $ (603 ) $ 327,981 $ (830 ) In Loss Position for More than 12 Months As of June 30, 2017 As of December 31, 2016 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Commercial paper and corporate bonds $ 25,200 $ (45 ) $ 68,158 $ (56 ) U.S. government agency debt securities 11,785 (15 ) 4,794 (6 ) Total $ 36,985 $ (60 ) $ 72,952 $ (62 )

Fair Value (Tables)

Fair Value (Tables)	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Financial assets and liabilities measured at fair value on a recurring basis	The following table summarizes, as of June 30, 2017 and December 31, 2016 , the Company's financial assets and liabilities that are measured at fair value on a recurring basis, according to the fair value hierarchy described in the significant accounting policies included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2016 (in thousands): As of June 30, 2017 As of December 31, 2016 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Cash $ 110,632 $ — $ — $ 110,632 $ 93,384 $ — $ — $ 93,384 Money market funds 76 — — 76 135 — — 135 Total cash and cash equivalents 110,708 — — 110,708 93,519 — — 93,519 Commercial paper and corporate bonds — 389,735 — 389,735 — 388,636 — 388,636 U.S. government agency debt securities — 34,562 — 34,562 — 33,067 — 33,067 Total marketable securities — 424,297 — 424,297 — 421,703 — 421,703 Total financial assets measured at fair value on a recurring basis $ 110,708 $ 424,297 $ — $ 535,005 $ 93,519 $ 421,703 $ — $ 515,222 Contingent consideration – short-term $ — $ — $ 3,965 $ 3,965 $ — $ — $ — $ — Contingent consideration – long-term — — 1,790 1,790 — — — — Total financial liabilities measured at fair value on a recurring basis $ — $ — $ 5,755 $ 5,755 $ — $ — $ — $ —
Changes in fair value of level 3 liabilities	The following table provides a summary of changes in fair value of the Company's Level 3 financial liabilities during the six months ended June 30, 2017 (in thousands): Balance as of January 1, 2017 $ — Contingent consideration — acquisition 5,697 Fair value adjustment (included in general and administrative expenses) 58 Balance as of June 30, 2017 $ 5,755

Acquisitions (Tables)

Acquisitions (Tables)	6 Months Ended
	Jun. 30, 2017
Business Combinations [Abstract]
Schedule of finite-lived intangibles acquired as part of a business combination	Intangible assets acquired were as follows (in thousands): Acquisition Date Fair Value Weighted-Average Useful Life Developed technology $ 15,602 5 years Customer relationships 890 6 years Non-competition agreements 110 3.5 years Total $ 16,602

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in the carrying amount of goodwill	The change in the carrying amount of goodwill during the six months ended June 30, 2017 was as follows (in thousands): Balance as of January 1, 2017 $ 30,780 Additions related to acquisitions 16,690 Foreign currency translation adjustments 208 Balance as of June 30, 2017 $ 47,678
Intangible assets	Total intangible assets are summarized as follows (in thousands): As of June 30, 2017 As of December 31, 2016 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Developed technology $ 24,386 $ (6,644 ) $ 17,742 $ 8,714 $ (5,098 ) $ 3,616 Customer relationships 4,475 (2,373 ) 2,102 3,566 (2,176 ) 1,390 Non-competition agreements 260 (90 ) 170 150 (66 ) 84 Total $ 29,121 $ (9,107 ) $ 20,014 $ 12,430 $ (7,340 ) $ 5,090
Annual amortization for the next five years	Future amortization of intangible assets is expected to be as follows (in thousands): Remainder of year ending December 31, 2017 $ 2,427 Years ending December 31, 2018 4,788 2019 4,530 2020 3,787 2021 3,517 2022 921 Thereafter 44 Total $ 20,014

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Components of convertible senior notes	The Company's 1.00% convertible senior notes (the "Notes"), issued in August 2013, consisted of the following components as of June 30, 2017 and December 31, 2016 (in thousands): June 30, December 31, Equity component, net of equity issue costs $ 60,222 $ 60,222 Liability component: Principal 287,500 287,500 Less: unamortized debt discount (15,469 ) (22,076 ) Less: unamortized debt issuance costs (1,384 ) (2,023 ) Net carrying amount $ 270,647 $ 263,401
Interest expense related to convertible senior notes	The following table sets forth total interest expense recognized related to the Notes for the three and six months ended June 30, 2017 and 2016 (in thousands except percentages): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Contractual interest expense $ 719 $ 719 $ 1,438 $ 1,438 Amortization of debt issuance costs 320 320 639 639 Amortization of debt discount 3,328 3,135 6,607 6,224 Total $ 4,367 $ 4,174 $ 8,684 $ 8,301 Effective interest rate 6.5 % 6.5 % 6.5 % 6.5 %

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Components of stock-based compensation expense	For the three and six months ended June 30, 2017 and 2016 , the components of stock-based compensation expense were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Stock options $ 938 $ 998 $ 1,855 $ 2,053 Restricted stock awards and units 7,769 6,263 14,688 11,741 Performance-based restricted stock units 3,074 2,235 4,702 4,869 Employee stock purchase plan 969 951 1,897 2,034 Total stock-based compensation (1) $ 12,750 $ 10,447 $ 23,142 $ 20,697 (1) Total stock-based compensation is presented in this table on a gross basis, consistent with the additional paid-in capital impact recorded in stockholders' equity. On the Company's consolidated statements of operations and consolidated statements of cash flows, stock-based compensation is presented net of foreign exchange impact and capitalization of eligible software development-related costs.
Fair value of stock option grants	The fair value of each stock option granted during the three and six months ended June 30, 2017 and 2016 was estimated on the date of grant using a Black-Scholes pricing model with the following weighted-average assumptions: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Expected volatility 43 % 44 % 44 % 43 % Expected life 6 years 6 years 6 years 6 years Risk-free interest rate 2.02 % 1.40 % 2.07 % 1.45 % Dividend yield — — — —
Summary of activities and changes in stock option plans	The following table summarizes the status of the Company's stock options as of June 30, 2017 , and changes during the six months then ended (in thousands, except per share data): Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (years) Aggregate Intrinsic Value Outstanding at January 1, 2017 1,793 $23.39 Granted 77 56.90 Exercised (268 ) 33.81 Forfeited (42 ) 44.08 Expired (7 ) 58.92 Outstanding at June 30, 2017 1,553 $22.53 4.70 $86,484 Exercisable at June 30, 2017 1,249 $16.18 3.76 $77,450 Vested and expected to vest at June 30, 2017 1,521 $21.97 4.61 $85,499
Summary of nonvested restricted stock awards	The following table summarizes the status of the Company’s nonvested time-based RSAs and RSUs as of June 30, 2017 , and changes during the six months then ended (in thousands, except per share data): Number of Shares Weighted- Average Grant Date Fair Value Nonvested at January 1, 2017 1,850 $40.89 Granted 727 56.91 Vested (537 ) 38.77 Forfeited (156 ) 41.40 Nonvested at June 30, 2017 1,884 $47.66
Fair value of TSR PBRSUs	The fair value of PBRSUs with market conditions granted during the six months ended June 30, 2017 and 2016 was estimated as of the date of grant using a Monte Carlo valuation model with the following weighted average assumptions: 2017 TSR PBRSUs 2016 TSR PBRSUs Expected volatility - Medidata 42 % 48 % Expected volatility - comparison index 43 % 43 % Expected life 2.85 years 2.84 years Risk-free interest rate 1.40 % 0.91 % Dividend yield — —
Summary of performance-based restricted stock units based on expected performance	The following table summarizes the status of the Company’s PBRSUs based upon expected performance as of June 30, 2017 , and changes during the six months then ended (in thousands, except per share data): Net Income TSR Other Total Number of Shares Weighted-Average Grant Date Fair Value Nonvested at January 1, 2017 — 390 2 392 $ 57.05 Granted (based on performance at 100% of targeted levels) 132 132 — 264 71.51 Adjustment related to expected performance 66 402 — 468 61.82 Vested — (92 ) — (92 ) 67.30 Forfeited — (26 ) — (26 ) 59.60 Nonvested at June 30, 2017 198 806 2 1,006 $ 62.06
Fair value of employee stock purchase plan shares	The fair value of shares granted under the Company's employee stock purchase plan ("ESPP") was estimated using a Black-Scholes pricing model with the following weighted-average assumptions: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Expected volatility 39 % 46 % 39 % 46 % Expected life 1.49 years 1.68 years 1.49 years 1.68 years Risk-free interest rate 0.62 % 0.58 % 0.62 % 0.58 % Dividend yield — — — —

Accumulated Other Comprehensi26

Accumulated Other Comprehensive Income (Tables)	6 Months Ended
	Jun. 30, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of accumulated other comprehensive loss	The changes in the balances of each component of accumulated other comprehensive loss during the six months ended June 30, 2017 were as follows (in thousands): Foreign currency translation adjustments Unrealized gains (losses) on marketable securities Total Balance as of January 1, 2017 $ (4,729 ) $ (547 ) $ (5,276 ) Other comprehensive income 1,302 148 1,450 Balance as of June 30, 2017 $ (3,427 ) $ (399 ) $ (3,826 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Reconciliation of the numerators and denominators of basic and diluted earnings per share	A reconciliation of the numerator and denominator of basic earnings per share and diluted earnings per share for the three and six months ended June 30, 2017 and 2016 is shown in the following table (in thousands, except per share data): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 (1) 2017 2016 (1) Numerator Net income $ 8,250 $ 6,210 $ 17,768 $ 10,785 Denominator Denominator for basic earnings per share: Weighted average common shares outstanding 56,433 55,392 56,254 55,255 Denominator for diluted earnings per share: Dilutive potential common shares: Stock options 1,001 980 976 977 Restricted stock awards and units 798 409 835 440 Performance-based restricted stock units 625 94 560 141 Employee stock purchase plan 149 — 114 — Convertible senior notes 829 — 312 — Weighted average common shares outstanding with assumed conversion 59,835 56,875 59,051 56,813 Basic earnings per share $ 0.15 $ 0.11 $ 0.32 $ 0.20 Diluted earnings per share $ 0.14 $ 0.11 $ 0.30 $ 0.19 (1) Prior period recast to reflect the Company's early adoption of ASU No. 2016-09 in the third quarter of 2016.
Schedule of antidilutive securities excluded from computation of earnings per share	Anti-dilutive common stock equivalents excluded from the calculation of diluted earnings per share for the three and six months ended June 30, 2017 and 2016 are shown in the following table (in thousands, except per share data): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 (1) 2017 2016 (1) Stock options 94 665 202 636 Restricted stock awards and units 1 132 10 121 Performance-based restricted stock units — — — 166 Employee stock purchase plan 275 233 275 233 Total 370 1,030 487 1,156 (1) Prior period recast to reflect the Company's early adoption of ASU No. 2016-09 in the third quarter of 2016.

Summary of Significant Accoun28

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Unbilled receivables	$ 12.5	$ 14.1

Stockholders' Equity (Details)

Stockholders' Equity (Details) - $ / shares	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Equity [Abstract]
Shares paid for tax withholding for share based compensation	260,737	326,568
Shares paid for tax withholding for share based compensation, average price	$ 56.71	$ 35.59
Forfeited restricted stock awards transferred to treasury stock	154,106	99,876
Par value of treasury stock	$ 0.01		$ 0.01

Investments (Details)

Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Marketable securities by security type
Cost	$ 424,944	$ 422,591
Gross unrealized gains	16	4
Gross unrealized losses	(663)	(892)
Estimated fair value	424,297	421,703
Commercial paper and corporate bonds [Member]
Marketable securities by security type
Cost	390,313	389,459
Gross unrealized gains	16	4
Gross unrealized losses	(594)	(827)
Estimated fair value	389,735	388,636
U.S. government agency debt securities [Member]
Marketable securities by security type
Cost	34,631	33,132
Gross unrealized gains	0	0
Gross unrealized losses	(69)	(65)
Estimated fair value	$ 34,562	$ 33,067

Investments (Details 1)

Investments (Details 1) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Marketable securities by contractual maturity
Cost	$ 424,944	$ 422,591
Estimated fair value	424,297	421,703
One year or less [Member]
Marketable securities by contractual maturity
Cost	256,720	281,591
Estimated fair value	256,401	281,285
One to five years [Member]
Marketable securities by contractual maturity
Cost	168,224	141,000
Estimated fair value	$ 167,896	$ 140,418

Investments (Details 2)

Investments (Details 2) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair market value and gross unrealized losses of marketable securities
Less than 12 months in unrealized loss position - fair value	$ 370,506	$ 327,981
Less than 12 months in unrealized loss position - gross unrealized losses	(603)	(830)
12 months or more in unrealized loss position - fair value	36,985	72,952
12 months or more in unrealized loss position - gross unrealized losses	(60)	(62)
Commercial paper and corporate bonds [Member]
Fair market value and gross unrealized losses of marketable securities
Less than 12 months in unrealized loss position - fair value	347,730	299,708
Less than 12 months in unrealized loss position - gross unrealized losses	(549)	(771)
12 months or more in unrealized loss position - fair value	25,200	68,158
12 months or more in unrealized loss position - gross unrealized losses	(45)	(56)
U.S. government agency debt securities [Member]
Fair market value and gross unrealized losses of marketable securities
Less than 12 months in unrealized loss position - fair value	22,776	28,273
Less than 12 months in unrealized loss position - gross unrealized losses	(54)	(59)
12 months or more in unrealized loss position - fair value	11,785	4,794
12 months or more in unrealized loss position - gross unrealized losses	$ (15)	$ (6)

Investments (Details Textual)

Investments (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Investments [Abstract]
Net realized gains (losses) from the sale of marketable securities	$ 0	$ 3	$ 1	$ 3
Cost method investment, description			The Company holds shares of Series B Preferred Stock of SHYFT Analytics, Inc. ("SHYFT"), purchased via a private placement. This investment is accounted for under the cost method and is included in other assets on the Company's consolidated balance sheet
Cost method investment, original cost	$ 4,000		$ 4,000

Fair Value (Details)

Fair Value (Details) - Fair value, recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Assets
Total cash and cash equivalents	$ 110,708	$ 93,519
Total marketable securities	424,297	421,703
Total financial assets	535,005	515,222
Cash [Member]
Assets
Total cash and cash equivalents	110,632	93,384
Money market funds [Member]
Assets
Total cash and cash equivalents	76	135
Commercial paper and corporate bonds [Member]
Assets
Total marketable securities	389,735	388,636
U.S. government agency debt securities [Member]
Assets
Total marketable securities	34,562	33,067
Contingent Consideration [Member]
Liabilities
Contingent consideration - short-term	3,965	0
Contingent consideration - long-term	1,790	0
Total financial liabilities	5,755	0
Level 1 [Member]
Assets
Total cash and cash equivalents	110,708	93,519
Total marketable securities	0	0
Total financial assets	110,708	93,519
Level 1 [Member] | Cash [Member]
Assets
Total cash and cash equivalents	110,632	93,384
Level 1 [Member] | Money market funds [Member]
Assets
Total cash and cash equivalents	76	135
Level 1 [Member] | Commercial paper and corporate bonds [Member]
Assets
Total marketable securities	0	0
Level 1 [Member] | U.S. government agency debt securities [Member]
Assets
Total marketable securities	0	0
Level 1 [Member] | Contingent Consideration [Member]
Liabilities
Contingent consideration - short-term	0	0
Contingent consideration - long-term	0	0
Total financial liabilities	0	0
Level 2 [Member]
Assets
Total cash and cash equivalents	0	0
Total marketable securities	424,297	421,703
Total financial assets	424,297	421,703
Level 2 [Member] | Cash [Member]
Assets
Total cash and cash equivalents	0	0
Level 2 [Member] | Money market funds [Member]
Assets
Total cash and cash equivalents	0	0
Level 2 [Member] | Commercial paper and corporate bonds [Member]
Assets
Total marketable securities	389,735	388,636
Level 2 [Member] | U.S. government agency debt securities [Member]
Assets
Total marketable securities	34,562	33,067
Level 2 [Member] | Contingent Consideration [Member]
Liabilities
Contingent consideration - short-term	0	0
Contingent consideration - long-term	0	0
Total financial liabilities	0	0
Level 3 [Member]
Assets
Total cash and cash equivalents	0	0
Total marketable securities	0	0
Total financial assets	0	0
Level 3 [Member] | Cash [Member]
Assets
Total cash and cash equivalents	0	0
Level 3 [Member] | Money market funds [Member]
Assets
Total cash and cash equivalents	0	0
Level 3 [Member] | Commercial paper and corporate bonds [Member]
Assets
Total marketable securities	0	0
Level 3 [Member] | U.S. government agency debt securities [Member]
Assets
Total marketable securities	0	0
Level 3 [Member] | Contingent Consideration [Member]
Liabilities
Contingent consideration - short-term	3,965	0
Contingent consideration - long-term	1,790	0
Total financial liabilities	$ 5,755	$ 0

Fair Value (Details 1)

Fair Value (Details 1) - Contingent Consideration [Member] $ in Thousands	6 Months Ended
	Jun. 30, 2017USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance as of beginning of period	$ 0
Contingent consideration, acquisition	5,697
Fair value adjustment	58
Balance as of end of period	$ 5,755

Fair Value (Details Textual)

Fair Value (Details Textual) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of financial assets between Level 1 and Level 2	$ 0	$ 0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs and techniques	Fair values of corporate bonds and U.S. government agency debt securities were derived from a consensus or weighted-average price based on input of market prices from multiple sources at each reporting period. With regard to commercial paper, all of the securities had high credit ratings and one year or less to maturity; therefore, fair value was derived from accretion of purchase price to face value over the term of maturity or quoted market prices for similar instruments if available.
Contingent Consideration [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs and techniques	The fair value of short-term contingent consideration, which is related to the achievement of a technical milestone, has been estimated using situation-based modeling, which considers the probability-weighted present value of the expected payout amount. Significant assumptions include the Company's expectations with regard to the likelihood and timing of achievement of the related technical milestone and a discount rate of 2.9%. The fair value of long-term contingent consideration, which is related to achievement of revenue targets, has been estimated using a Monte Carlo simulation to simulate future performance of the acquired business under a risk-neutral framework; significant assumptions include a risk-adjusted discount rate of 10.2% and revenue volatility of 8.0%.

Acquisitions (Details)

Acquisitions (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017USD ($)
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 16,602
Developed technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 15,602
Useful life	5 years
Customer relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 890
Useful life	6 years
Non-competition agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 110
Useful life	3 years 6 months

Acquisitions (Details Textual)

Acquisitions (Details Textual) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Feb. 17, 2017
Business Acquisition [Line Items]
Control obtained description	The Company acquired all outstanding equity interests
Reason for business combinations	Through these acquisitions, the Company adds regulated document and standard operating procedure ("SOP") management, electronic trial master file ("eTMF"), and eConsent capabilities to its platform.
Total consideration	$ 28.9
Acquisition date fair value of contingent consideration liability		$ 5.7
Deferred tax liability recognized	2.9
Net tangible assets acquired (liabilities assumed)	$ 1.5
CHITA [Member]
Business Acquisition [Line Items]
Name of acquired entity	CHITA Inc. ("CHITA")
Effective date of acquisition	Feb. 17, 2017
Description of acquired entity	CHITA provides regulated content management for the life sciences industry.
Mytrus [Member]
Business Acquisition [Line Items]
Name of acquired entity	Mytrus, Incorporated ("Mytrus")
Effective date of acquisition	Apr. 18, 2017
Description of acquired entity	Mytrus provides cloud-based software for electronic informed consent ("eConsent"), which replaces paper patient consent forms.

Goodwill and Intangible Asset39

Goodwill and Intangible Assets (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017USD ($)
Changes in the carrying amount of goodwill
Balance as of beginning of period	$ 30,780
Additions related to acquisition	16,690
Foreign currency translation adjustments	208
Balance as of end of period	$ 47,678

Goodwill and Intangible Asset40

Goodwill and Intangible Assets (Details 1) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Intangible assets
Gross carrying amount	$ 29,121	$ 12,430
Accumulated amortization	(9,107)	(7,340)
Net carrying amount	20,014	5,090
Developed technology [Member]
Intangible assets
Gross carrying amount	24,386	8,714
Accumulated amortization	(6,644)	(5,098)
Net carrying amount	17,742	3,616
Customer relationships [Member]
Intangible assets
Gross carrying amount	4,475	3,566
Accumulated amortization	(2,373)	(2,176)
Net carrying amount	2,102	1,390
Non-competition agreements [Member]
Intangible assets
Gross carrying amount	260	150
Accumulated amortization	(90)	(66)
Net carrying amount	$ 170	$ 84

Goodwill and Intangible Asset41

Goodwill and Intangible Assets (Details 2) $ in Thousands	Jun. 30, 2017USD ($)
Annual amortization for the next five years
Remainder of year current year	$ 2,427
Next twelve months	4,788
Year two	4,530
Year three	3,787
Year four	3,517
Year five	921
Thereafter	$ 44

Debt (Details)

Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Components of convertible senior notes
Equity component net of equity issue costs	$ 60,222	$ 60,222
Principal amount	287,500	287,500
Unamortized discount	(15,469)	(22,076)
Unamortized debt issuance costs	(1,384)	(2,023)
Convertible senior notes, net carrying amount	$ 270,647	$ 263,401

Debt (Details 1)

Debt (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Interest expense on convertible senior notes
Convertible senior notes, contractual interest expense	$ 719	$ 719	$ 1,438	$ 1,438
Amortization of debt issuance costs	320	320	639	639
Amortization of debt discount	3,328	3,135	6,607	6,224
Convertible senior notes, total interest expense	$ 4,367	$ 4,174	$ 8,684	$ 8,301
Convertible senior notes, effective interest rate during period	6.50%	6.50%	6.50%	6.50%

Debt (Details Textual)

Debt (Details Textual) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Aug. 12, 2013
Convertible senior notes
Conversion price			$ 58.05
Closing price of the Company's common stock	$ 78.20
If-converted value in excess of principal	$ 99.8
Approximate remaining life	13 months
Convertible Debt [Member] | Fair Value, Inputs, Level 2 [Member]
Convertible senior notes
Approximate fair value	$ 398.6	$ 314.4

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Components of stock-based compensation expense
Total stock-based compensation	[1]	$ 12,750	$ 10,447	$ 23,142	$ 20,697
Stock options [Member]
Components of stock-based compensation expense
Total stock-based compensation		938	998	1,855	2,053
Restricted stock awards and units [Member]
Components of stock-based compensation expense
Total stock-based compensation		7,769	6,263	14,688	11,741
Performance-based restricted stock units [Member]
Components of stock-based compensation expense
Total stock-based compensation		3,074	2,235	4,702	4,869
Employee stock purchase plan [Member]
Components of stock-based compensation expense
Total stock-based compensation		$ 969	$ 951	$ 1,897	$ 2,034
[1]	Total stock-based compensation is presented in this table on a gross basis, consistent with the additional paid-in capital impact recorded in stockholders' equity. On the Company's consolidated statements of operations and consolidated statements of cash flows, stock-based compensation is presented net of foreign exchange impact and capitalization of eligible software development-related costs.

Stock-Based Compensation (Det46

Stock-Based Compensation (Details 1) - Stock options [Member]	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Weighted-average Black-Scholes assumptions used to estimate fair value of stock options granted
Expected volatility	43.00%	44.00%	44.00%	43.00%
Expected term	6 years	6 years	6 years	6 years
Risk-free interest rate	2.02%	1.40%	2.07%	1.45%
Dividend yield	0.00%	0.00%	0.00%	0.00%

Stock-Based Compensation (Det47

Stock-Based Compensation (Details 2) - Stock options [Member] $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2017USD ($)$ / sharesshares
Summary of activities and changes in stock option plans
Number of shares outstanding at beginning of period | shares	1,793
Weighted-average exercise price outstanding at beginning of period | $ / shares	$ 23.39
Number of shares granted | shares	77
Weighted-average exercise price granted | $ / shares	$ 56.90
Number of shares exercised | shares	(268)
Weighted-average exercise price exercised | $ / shares	$ 33.81
Number of shares forfeited | shares	(42)
Weighted-average exercise price forfeited | $ / shares	$ 44.08
Number of shares expired | shares	(7)
Weighted-average exercise price expired | $ / shares	$ 58.92
Number of shares outstanding at end of period | shares	1,553
Weighted-average exercise price outstanding at end of period | $ / shares	$ 22.53
Weighted average remaining contractual term outstanding at end of period	4 years 8 months 13 days
Aggregate intrinsic value outstanding at end of period | $	$ 86,484
Number of shares exercisable at end of period | shares	1,249
Weighted-average exercise price exercisable at end of period | $ / shares	$ 16.18
Weighted average remaining contractual term exercisable at end of period	3 years 9 months 3 days
Aggregate intrinsic value exercisable at end of period | $	$ 77,450
Number of shares vested and expected to vest at end of period | shares	1,521
Weighted-average exercise price vested and expected to vest at end of period | $ / shares	$ 21.97
Weighted average remaining contractual term vested and expected to vest at end of period	4 years 7 months 11 days
Aggregate intrinsic value vested and expected to vest at end of period | $	$ 85,499

Stock-Based Compensation (Det48

Stock-Based Compensation (Details 3) - Restricted stock awards and units [Member] shares in Thousands	6 Months Ended
	Jun. 30, 2017$ / sharesshares
Summary of time-based nonvested restricted stock awards and units
Nonvested number of shares/units at beggining of period | shares	1,850
Nonvested weighted-average grant-date fair value at beginning of period | $ / shares	$ 40.89
Granted number of shares | shares	727
Granted weighted-average grant-date fair value | $ / shares	$ 56.91
Vested number of shares/units | shares	(537)
Vested weighted-average grant-date fair value | $ / shares	$ 38.77
Forfeited number of shares/units | shares	(156)
Forfeited weighted-average grant-date fair value | $ / shares	$ 41.40
Nonvested number of shares/units at end of period | shares	1,884
Nonvested weighted-average grant-date fair value at end of period | $ / shares	$ 47.66

Stock-Based Compensation (Det49

Stock-Based Compensation (Details 4) - Performance-based restricted stock units [Member] - TSR [Member]	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Assumptions used to estimate fair value of TSR PBRSUs
Expected volatility - Medidata	42.00%	48.00%
Expected volatility - Comparison index	43.00%	43.00%
Expected term	2 years 10 months 5 days	2 years 10 months 4 days
Risk-free interest rate	1.40%	0.91%
Dividend yield	0.00%	0.00%

Stock-Based Compensation (Det50

Stock-Based Compensation (Details 5) - Performance-based restricted stock units [Member] shares in Thousands	6 Months Ended
	Jun. 30, 2017$ / sharesshares
Summary of performance-based restricted stock units based upon expected performance
Nonvested number of shares/units at beggining of period	392
Nonvested weighted-average grant-date fair value at beginning of period | $ / shares	$ 57.05
Granted number of units (based on performance at 100% of targeted levels)	264
Granted weighted-average grant-date fair value | $ / shares	$ 71.51
Adjustment due to expected performance	468
Adjustment due to expected performance weighted average grant date fair value | $ / shares	$ 61.82
Vested number of shares/units	(92)
Vested weighted-average grant-date fair value | $ / shares	$ 67.30
Forfeited number of shares/units	(26)
Forfeited weighted-average grant-date fair value | $ / shares	$ 59.60
Nonvested number of shares/units at end of period	1,006
Nonvested weighted-average grant-date fair value at end of period | $ / shares	$ 62.06
Net income [Member]
Summary of performance-based restricted stock units based upon expected performance
Nonvested number of shares/units at beggining of period	0
Granted number of units (based on performance at 100% of targeted levels)	132
Adjustment due to expected performance	66
Vested number of shares/units	0
Forfeited number of shares/units	0
Nonvested number of shares/units at end of period	198
TSR [Member]
Summary of performance-based restricted stock units based upon expected performance
Nonvested number of shares/units at beggining of period	390
Granted number of units (based on performance at 100% of targeted levels)	132
Adjustment due to expected performance	402
Vested number of shares/units	(92)
Forfeited number of shares/units	(26)
Nonvested number of shares/units at end of period	806
Sales Goals [Member]
Summary of performance-based restricted stock units based upon expected performance
Nonvested number of shares/units at beggining of period	2
Granted number of units (based on performance at 100% of targeted levels)	0
Adjustment due to expected performance	0
Vested number of shares/units	0
Forfeited number of shares/units	0
Nonvested number of shares/units at end of period	2

Stock-Based Compensation (Det51

Stock-Based Compensation (Details 6) - Employee stock purchase plan [Member]	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Weighted-average Black-Scholes assumptions used to estimate fair value of ESPP shares
Expected volatility	39.00%	46.00%	39.00%	46.00%
Expected term	1 year 5 months 25 days	1 year 8 months 4 days	1 year 5 months 25 days	1 year 8 months 4 days
Risk-free interest rate	0.62%	0.58%	0.62%	0.58%
Dividend yield	0.00%	0.00%	0.00%	0.00%

Stock-Based Compensation (Det52

Stock-Based Compensation (Details Textual) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Stock based compensation (Textual) [Abstract]
Incremental expense associated with equity modifications	$ 0	$ 0.1	$ 0.1	$ 0.3
Stock options [Member]
Stock based compensation (Textual) [Abstract]
Weighted-average grant-date fair value of stock options granted	$ 25.37	$ 17.34	$ 25.47	$ 17.14
Total intrinsic value of stock options exercised	$ 4	$ 2.3	$ 8	$ 3
Total fair value of shares vested	1	1.3	2.1	2.1
Unrecognized compensation cost related to non-vested stock-based compensation awards granted	5.9		$ 5.9
Weighted-average remaining period over which cost is expected to be recognized			2 years 6 months 29 days
Restricted stock awards and units [Member]
Stock based compensation (Textual) [Abstract]
Total fair value of shares vested	4.7	7.5	$ 31	16.9
Unrecognized compensation cost related to non-vested stock-based compensation awards granted	76.7		$ 76.7
Weighted-average remaining period over which cost is expected to be recognized			2 years 9 months 5 days
Performance-based restricted stock units [Member]
Stock based compensation (Textual) [Abstract]
Total fair value of shares vested	0	$ 0	$ 5.1	$ 10
Unrecognized compensation cost related to non-vested stock-based compensation awards granted	$ 26.4		$ 26.4
Weighted-average remaining period over which cost is expected to be recognized			2 years
Target number of performance-based restricted stock units granted during the period	0	0
Performance-based restricted stock units [Member] | TSR [Member]
Stock based compensation (Textual) [Abstract]
Target number of performance-based restricted stock units granted during the period			132	223
Award terms			market conditions based on the Company's total stockholder return ("TSR") relative to that of the Russell 2000 Index over the three-year period ending December 31, 2019, vesting in full in three years with the number of shares ultimately earned ranging from zero to 200% of the target number of shares	market conditions based on the Company's TSR relative to that of the Russell 2000 Index over the three-year period ending December 31, 2018, vesting in full in three years with the number of shares ultimately earned ranging from zero to 200% of the target number of shares
Performance-based restricted stock units [Member] | Net income [Member]
Stock based compensation (Textual) [Abstract]
Target number of performance-based restricted stock units granted during the period			132
Award terms			performance conditions based on the compound annual growth rate of net income over the three-year period ending December 31, 2019, vesting in full in three years with the number of shares ultimately earned ranging from zero to 200% of the target number of shares.
Employee stock purchase plan [Member]
Stock based compensation (Textual) [Abstract]
Unrecognized compensation cost related to non-vested stock-based compensation awards granted	$ 3.4		$ 3.4
Weighted-average remaining period over which cost is expected to be recognized			1 year 14 days
Shares issued during period under employee stock purchase plan	103	89	103	89
Weighted-average purchase price of shares issued during period under employee stock purchase plan	$ 40.50	$ 38.35	$ 40.50	$ 38.35

Accumulated Other Comprehensi53

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated other comprehensive income
Balance as of beginning of period			$ (5,276)
Other comprehensive income (loss), net of tax	$ 958	$ (747)	1,450	$ 474
Balance as of end of period	(3,826)		(3,826)
Unrealized gains (losses) on available for sale securities
Accumulated other comprehensive income
Balance as of beginning of period			(547)
Other comprehensive income (loss), net of tax			148
Balance as of end of period	(399)		(399)
Foreign currency translation adjustments
Accumulated other comprehensive income
Balance as of beginning of period			(4,729)
Other comprehensive income (loss), net of tax			1,302
Balance as of end of period	$ (3,427)		$ (3,427)

Accumulated Other Comprehensi54

Accumulated Other Comprehensive Income (Details Textual) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Reclassifications from accumulated other comprehensive income	$ 1	$ 3

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016		Jun. 30, 2017	Jun. 30, 2016
Reconciliation of the numerators and denominators of basic and diluted earnings per share
Net income	$ 8,250	$ 6,210	[1]	$ 17,768	$ 10,785	[1]
Weighted average common shares outstanding	56,433	55,392		56,254	55,255
Dilutive potential common shares:
Stock options	1,001	980	[1]	976	977	[1]
Restricted stock awards and units	798	409	[1]	835	440	[1]
Performance-based restricted stock units	625	94	[1]	560	141	[1]
Employee stock purchase plan	149	0	[1]	114	0	[1]
Convertible senior notes	829	0	[1]	312	0	[1]
Weighted average common shares outstanding with assumed conversion	59,835	56,875	[1]	59,051	56,813	[1]
Basic earnings per share	$ 0.15	$ 0.11	[1]	$ 0.32	$ 0.20	[1]
Diluted earnings per share	$ 0.14	$ 0.11	[1]	$ 0.30	$ 0.19	[1]
[1]	Prior periods recast to reflect the Company's early adoption of Accounting Standards Update No. 2016-09 in the third quarter of 2016

Earnings Per Share (Details 1)

Earnings Per Share (Details 1) - shares shares in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	[1]	Jun. 30, 2017	Jun. 30, 2016	[1]
Antidilutive common stock equivalents excluded from the calculation of diluted earnings per share
Antidilutive shares excluded from calculation of diluted earnings (loss) per share	370	1,030		487	1,156
Stock options [Member]
Antidilutive common stock equivalents excluded from the calculation of diluted earnings per share
Antidilutive shares excluded from calculation of diluted earnings (loss) per share	94	665		202	636
Restricted stock awards and units [Member]
Antidilutive common stock equivalents excluded from the calculation of diluted earnings per share
Antidilutive shares excluded from calculation of diluted earnings (loss) per share	1	132		10	121
Performance-based restricted stock units [Member]
Antidilutive common stock equivalents excluded from the calculation of diluted earnings per share
Antidilutive shares excluded from calculation of diluted earnings (loss) per share	0	0		0	166
Employee stock purchase plan [Member]
Antidilutive common stock equivalents excluded from the calculation of diluted earnings per share
Antidilutive shares excluded from calculation of diluted earnings (loss) per share	275	233		275	233
[1]	Prior periods recast to reflect the Company's early adoption of Accounting Standards Update No. 2016-09 in the third quarter of 2016

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Gross unrecognized tax benefits	$ 2.9	$ 2.9
Changes in tax position	$ 0

Commitments and Contingencies (

Commitments and Contingencies (Details)	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Legal matters	The Company is subject to legal proceedings and claims that arise in the ordinary course of business and records an estimated liability for these matters when an adverse outcome is considered to be probable and can be reasonably estimated. Although the outcome of the litigation cannot be predicted with certainty and some lawsuits, claims, or proceedings may be disposed of unfavorably to the Company, which could materially and adversely affect its financial condition or results of operations, the Company does not believe that it is currently a party to any material legal proceedings.
Standard product warranty description	The Company typically provides contractual warranties to its customers covering its solutions and services. To date, any refunds provided to customers have been immaterial.
Description of executive change in control agreements	The Company has change in control agreements with its chief executive officer and certain other executive officers. These agreements provide for payments to be made to such officers upon involuntary termination of their employment by the Company without cause or by such officers for good reason as defined in the agreements, within a period of 2 years following a change in control. The agreements provide that, upon a qualifying termination event, such officers will be entitled to (a) a severance payment equal to the sum of the officer’s base salary and target bonus amount (except that such payment for the Company's chief executive officer and president would be two times such sum); (b) continuation of health benefits for one year (except that such continuation for the Company's chief executive officer and president would be for two years); and (c) immediate vesting of remaining unvested equity awards, unless otherwise specified in the equity award agreements.
Wire transaction claim	In September 2014, the Company discovered that it had been the victim of a crime involving the fraudulently induced transfer of $4.8 million. The Company filed an insurance claim for its loss, and its insurer, Federal Insurance Co. ("Federal"), denied coverage. The Company commenced legal action, alleging that Federal had wrongly denied coverage. On July 21, 2017, the United States District Court for the Southern District of New York granted the Company's motion for summary judgment, and denied Federal's motion.