Medpace (MEDP) 10-K 26 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Feb. 22, 2019	Jun. 30, 2018
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Trading Symbol	MEDP
Entity Registrant Name	Medpace Holdings, Inc.
Entity Central Index Key	1,668,397
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Extended Transition Period	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		35,688,784
Entity Public Float			$ 635

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 23,275	$ 26,485
Restricted cash	7	7
Accounts receivable and unbilled, net (includes $3.8 million and $1.0 million with related parties at December 31, 2018 and 2017, respectively)	133,449	83,079
Prepaid expenses and other current assets	21,383	20,400
Total current assets	178,114	129,971
Property and equipment, net	52,255	48,739
Goodwill	660,981	660,981
Intangible assets, net	69,179	98,740
Deferred income taxes	713	6,343
Other assets	6,691	5,943
Total assets	967,933	950,717
Current liabilities:
Accounts payable (includes $0.3 million and $0.2 million with related parties at December 31, 2018 and 2017, respectively)	16,737	16,674
Accrued expenses	87,493	23,673
Pre-funded study costs (includes $1.0 million with related parties at December 31, 2017)	0	57,406
Advanced billings (includes $0.4 million and $1.7 million with related parties at December 31, 2018 and 2017, respectively)	147,935	73,756
Current portion of long-term debt	0	16,500
Other current liabilities	4,861	4,697
Total current liabilities	257,026	192,706
Long-term debt, net, less current portion	79,721	205,111
Deemed landlord liability, less current portion	24,484	26,602
Deferred income tax liability	439	560
Deferred credit	3,756	11,468
Other long-term liabilities	12,804	10,740
Total liabilities	378,230	447,187
Commitments and contingencies (see Note 9)
Shareholders’ equity:
Preferred stock - $0.01 par-value; 5,000,000 shares authorized; no shares issued and outstanding at December 31, 2018 and 2017, respectively	0	0
Common stock - $0.01 par-value; 250,000,000 shares authorized at December 31, 2018 and 2017, respectively; 35,665,910 and 35,466,510 shares issued and outstanding at December 31, 2018 and 2017, respectively	356	355
Treasury stock - 200,000 shares at December 31, 2018 and 2017, respectively	(6,030)	(6,030)
Additional paid-in capital	639,381	630,341
Accumulated deficit	(41,487)	(120,402)
Accumulated other comprehensive loss	(2,517)	(734)
Total shareholders’ equity	589,703	503,530
Total liabilities and shareholders’ equity	$ 967,933	$ 950,717

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Accounts receivable, unbilled services with related parties	$ 3.8	$ 1
Accounts payable includes related parties	0.3	0.2
Pre-funded study costs with related parties		1
Advanced billings with related parties	$ 0.4	$ 1.7
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock shares authorized	5,000,000	5,000,000
Preferred stock shares issued	0	0
Preferred stock shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock shares authorized	250,000,000	250,000,000
Common stock shares issued	35,665,910	35,466,510
Common stock shares outstanding	35,665,910	35,466,510
Treasury stock shares	200,000	200,000

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue:
Total revenue	$ 704,589	$ 436,152	$ 421,582
Operating expenses:
Direct service costs, excluding depreciation and amortization	252,284	211,773	198,510
Reimbursed out-of-pocket expenses	236,775	49,690	50,961
Total direct costs	489,059	261,463	249,471
Selling, general and administrative	75,681	63,357	61,507
Depreciation	9,240	8,574	7,442
Amortization	29,561	37,900	50,672
Total operating expenses	603,541	371,294	369,092
Income from operations	101,048	64,858	52,490
Other expense, net:
Loss on extinguishment of debt	0	0	(10,726)
Miscellaneous income (expense), net	1,060	(354)	(423)
Interest expense, net	(8,157)	(7,559)	(19,384)
Total other expense, net	(7,097)	(7,913)	(30,533)
Income before income taxes	93,951	56,945	21,957
Income tax provision	20,766	17,823	8,532
Net income	$ 73,185	$ 39,122	$ 13,425
Net income per share attributable to common shareholders:
Basic	$ 2.05	$ 1	$ 0.38
Diluted	$ 1.97	$ 0.98	$ 0.37
Weighted average common shares outstanding:
Basic	35,547	39,056	35,690
Diluted	36,912	39,839	36,329
Revenue Net
Revenue:
Total revenue	$ 704,589	$ 0	$ 0
Direct Service Revenue
Revenue:
Total revenue	0	386,462	370,621
Reimbursed Out of Pocket Revenue
Revenue:
Total revenue	$ 0	$ 49,690	$ 50,961

CONSOLIDATED STATEMENTS OF OP_2

CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Direct Service Revenue
Revenue with related parties	$ 11.1	$ 24.1
Reimbursed Out of Pocket Revenue
Revenue with related parties	$ 1.5	$ 5.4

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 73,185	$ 39,122	$ 13,425
Other comprehensive (loss) income
Foreign currency translation adjustments, net of taxes	(1,783)	3,008	(1,183)
Comprehensive income	$ 71,402	$ 42,130	$ 12,242

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	AOCI Attributable to Parent
Balance at Dec. 31, 2015	$ 413,474	$ 326		$ 438,716	$ (23,009)	$ (2,559)
Net income	13,425				13,425
Foreign currency translation	(1,183)					(1,183)
Stock-based compensation expense	2,777	1		2,776
Stock options exercised	678			678
Issuance of common stock	173,578	80		173,498
Common stock issuance costs	(2,719)			(2,719)
Reclassification of liability classified stock options upon IPO	10,463			10,463
Tax effect of initial public offering related costs	192			192
Tax benefit from stock-based compensation	25			25
Balance at Dec. 31, 2016	610,710	407		623,629	(9,584)	(3,742)
Impact to Retained Earnings from adoption | ASU 2016-09				440	(440)
Balance	610,710	407		624,069	(10,024)	(3,742)
Net income	39,122				39,122
Foreign currency translation	3,008					3,008
Stock-based compensation expense	4,463			4,463
Stock options exercised	1,812	1		1,811
Repurchases of common stock	(149,551)	(51)			(149,500)
Treasury stock purchases	(6,032)	(2)	$ (6,030)
Tax effect of initial public offering related costs	(2)			(2)
Balance at Dec. 31, 2017	503,530	355	(6,030)	630,341	(120,402)	(734)
Impact to Retained Earnings from adoption | ASU 2014-09	5,730				5,730
Balance	509,260	355	(6,030)	630,341	(114,672)	(734)
Net income	73,185				73,185
Foreign currency translation	(1,783)					(1,783)
Stock-based compensation expense	6,499			6,499
Stock options exercised	2,542	1		2,541
Balance at Dec. 31, 2018	$ 589,703	$ 356	$ (6,030)	$ 639,381	$ (41,487)	$ (2,517)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 73,185	$ 39,122	$ 13,425
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	9,240	8,574	7,442
Amortization	29,561	37,900	50,672
Stock-based compensation expense	6,499	4,463	9,815
Amortization of debt issuance costs and discount	615	662	2,576
Loss on extinguishment of debt	0	0	10,726
Deferred income tax provision (benefit)	3,942	3,237	(9,006)
Amortization and adjustment of deferred credit	(7,712)	(8,781)	0
Other	1,653	(673)	(1,019)
Changes in assets and liabilities:
Accounts receivable and unbilled, net	(27,047)	(2,898)	(13,727)
Prepaid expenses and other current assets	(1,241)	(3,533)	(3,661)
Accounts payable	1,342	4,816	691
Accrued expenses	29,029	(1,313)	4,516
Pre-funded study costs	0	5,292	5,400
Advanced billings	35,593	7,735	14,723
Other assets and liabilities, net	1,925	2,782	(841)
Net cash provided by operating activities	156,584	97,385	91,732
CASH FLOWS FROM INVESTING ACTIVITIES:
Property and equipment expenditures	(16,024)	(11,724)	(13,537)
Acquisition of intangibles	0	(569)	0
Other	(949)	56	115
Net cash used in investing activities	(16,973)	(12,237)	(13,422)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment for common stock issuance costs	0	0	(2,719)
Proceeds from stock option exercises	2,489	1,812	537
Repurchases of common stock	0	(155,583)	0
Excess tax benefit from stock-based compensation	0	0	25
Proceeds from issuance of debt, net of original issue discount	0	0	164,506
Payment of debt	(72,188)	(12,375)	(390,060)
Proceeds from revolving loan	0	100,000	0
Payments on revolving loan	(70,000)	(30,000)	0
Debt issuance costs	0	0	(1,802)
Payment of deemed landlord liability	(1,881)	(1,682)	(1,525)
Payment on debt extinguishment	0	0	(548)
Proceeds from common stock issued, net	0	0	173,578
Net cash used in financing activities	(141,580)	(97,828)	(58,008)
EFFECT OF EXCHANGE RATES ON CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	(1,241)	1,765	(632)
(DECREASE) INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	(3,210)	(10,915)	19,670
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH — Beginning of period	26,492	37,407	17,737
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH — End of period	23,282	26,492	37,407
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION—
Cash paid during the period for income taxes	23,311	17,180	17,654
Cash paid during the period for interest	7,589	6,888	16,895
Acquisition of property and equipment—non-cash	$ 1,551	$ 678	$ 1,687

Basis of Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	1. BASIS OF PRESENTATION Description of Business Medpace Holdings, Inc. together with its subsidiaries, (“Medpace” or the “Company”), a Delaware corporation, is a global provider of clinical research-based drug and medical device development services. The Company partners with pharmaceutical, biotechnology, and medical device companies in the development and execution of clinical trials. The Company’s drug development services focus on full service Phase I-IV clinical development services and include development plan design, coordinated central laboratory, project management, regulatory affairs, clinical monitoring, data management and analysis, pharmacovigilance new drug application submissions, and post-marketing clinical support. The Company also provides bio-analytical laboratory services, clinical human pharmacology, imaging services, and electrocardiography reading support for clinical trials. The Company’s operations are principally based in North America, Europe, and Asia. Share Repurchases In November 2017, approved an agreement to repurchase 2,000,000 shares of the Company’s common stock from Cinven in connection with the Secondary Offering (as described below) for aggregate consideration of approximately $60.3 million, representing a purchase price of $30.16 per share. In August 2017, the Disinterested Directors of the Company approved a stock repurchase agreement with Medpace Limited Partnership, a Guernsey limited partnership (the “Limited Partnership” acting through its general partner, Medpace GP Limited, a Guernsey company, the “General Partner” and, the Limited Partnership acting through the General Partner, “Cinven”), pursuant to which the Company repurchased 2,000,000 shares of the Company’s common stock from Cinven for aggregate consideration of approximately $60.5 million, representing a purchase price of $30.27 per share. The Company funded the repurchase with cash on hand and $40.0 million in borrowings under our Senior Secured Revolving Credit Facility. In April 2017, the Board of the Company authorized a share repurchase program with an authorized repurchase level of $50.0 million. The share repurchase program was cancelled in the fourth quarter of 2017. Repurchases under the repurchase program took place in the open market or negotiated transactions, at the discretion of the Company’s management. During the year ended December 31, 2017, the Company repurchased 1,342,786 shares of its outstanding common stock for $34.7 million under this share repurchase program. The Company has elected to constructively retire all repurchased shares with all amounts paid in excess of Common stock par value reflected within Accumulated deficit in the Company’s consolidated balance sheets, except for 200,000 shares, which are reflected within treasury stock in the Company’s consolidated balance sheets. Initial Public Offering On August 11, 2016, the Company's common stock began trading on the NASDAQ Global Select Market (“NASDAQ”) under the symbol "MEDP". On August 16, 2016, the Company completed its initial public offering (“IPO”) of its common stock at a price to the public of $23.00 per share. The Company issued and sold 8,050,000 shares of common stock in the IPO, including 1,050,000 common shares issued pursuant to the full exercise of the underwriters' option to purchase additional shares. The IPO raised net proceeds of approximately $173.6 million after deducting underwriting discounts and commissions. As contemplated in the Company’s prospectus filed pursuant to Rule 424(b) under the Securities Act of 1933, as amended (the “Securities Act”), with the Securities and Exchange Commission on August 11, 2016, the net proceeds from the IPO, along with cash on hand, were used to repay $175.0 million of outstanding borrowings under the 2014 Senior Secured Term Loan Facility (as defined below) and $2.7 million of offering expenses. Secondary Offerings During the year ended December 31, 2018, Cinven sold a total of 16,399,997 shares of the Company’s common stock as part of multiple secondary offerings. The Company incurred professional fees in connection with the secondary offerings of $0.7 million during the year ended December 31, 2018. The fees are included within operating expenses in the accompanying consolidated statement of operations. As of August 27, 2018, Cinven does not beneficially own any shares of the Company’s outstanding common stock. The Company did not sell any shares in or receive any proceeds from the secondary offerings. During the year ended December 31, 2017, Cinven sold a total of 4,600,000 shares of the Company’s common stock as part of a secondary offering. The Company incurred professional fees in connection with the secondary offering of $0.4 million during year ended December 31, 2017. The fees are included within operating expenses in the accompanying consolidated statement of operations.

Acquisition

Acquisition	12 Months Ended
	Dec. 31, 2018
Asset Acquisition [Abstract]
Acquisition	2. ACQUISITION In May 2017, the Company acquired out of bankruptcy NephroGenex, Inc. (“Nephrogenex” or the “Debtor”), a publicly-held pharmaceutical company that had previously filed for relief under Chapter 11 of the United States Bankruptcy Code. The Company, which was the largest unsecured creditor of Nephrogenex, entered into an agreement through the bankruptcy process, to exchange its unsecured claim for 100% of the common stock in the post-bankruptcy, debt-free Debtor. The assets of the acquired Debtor consist primarily of tax attributes as well as in-process research and development and other intangible assets. An analysis by the Company determined that substantially all the fair value of the assets on the date of acquisition is captured in the tax attributes, as the intangible assets account for a relatively immaterial portion of the fair market value of the total assets received. The acquisition of the Debtor was accounted for as an asset purchase. The Company allocated its consideration paid of $1.2 million, consisting of accounts receivable and unbilled receivables and transaction related costs, on a pro rata basis to the assets acquired based on their respective fair values. Acquired assets include intangible assets of $0.5 million, deferred tax assets of $22.2 million, consisting of tax effected net operating losses in the amount of $13.5 million, tax effected capitalized research and development expenses of $8.5 million and tax effected federal tax credits of $0.2 million, and deferred tax liabilities of $0.1 million. The excess amount of fair value received over consideration paid of $21.4 million was recorded as a Deferred credit in the consolidated balance sheets and is recognized within income tax provision in proportion to the realization of the deferred tax assets and federal tax credits prospectively. During the fourth quarter of the year ended December 31, 2017, the Deferred tax assets and related Deferred credit balances were revalued due primarily to the impact of tax reform. See Note 12 of the Notes to Consolidated Financial Statements for further discussion of the impact of tax reform on our consolidated financial statements. Additionally, in 2018, the Company disposed of approximately $7.4 million in deferred tax assets and reduced the Deferred credit by approximately $6.9 million as a result of an IRC Section 382 ownership shift that occurred as a result of Cinven’s sales of the Company’s securities. The ownership shift resulted in a limitation in the ability to utilize the acquired tax attributes and resulted in the described asset write-off and reduction of the Deferred credit.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	3. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Principles of Consolidation and Presentation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“US GAAP”) and include the accounts and operations of the Company and its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from these estimates. Significant items that are subject to management estimates and assumptions include revenue, net, allowances for doubtful accounts, acquisition purchase price allocations, long-lived asset impairment and useful lives, exit liabilities, stock-based compensation, uncertain income tax positions and contingencies. Reportable Segments The Company emphasizes its full service outsourcing model, providing services focused on the development, management and execution of clinical trials. As part of this full service approach, the Company utilizes centralized systems, customer interface technology, support functions and processes that cross service offerings and align resources to deliver efficient clinical trial services. Given the full service approach, the chief executive officer, who is the chief operating decision maker (“CODM”) assesses the allocation of resources based on key metrics including revenue, backlog, and net awards by service offering and consolidated profitability and consolidated cash flows. Based on the Company’s full service model, internal management and reporting structure, and key metrics used by the CODM to make resource allocation decisions, management has determined that the Company’s operations consist of a single operating segment. Therefore, results of operations are presented as a single reportable segment. Foreign Currencies Assets and liabilities recorded in foreign currencies on foreign subsidiary financial statements are translated at the exchange rate on the balance sheet date, while equity accounts are translated at historical exchange rates. Revenue and expenses are recorded at average rates of exchange during the year. Translation adjustments are recorded to Accumulated other comprehensive loss in the consolidated statements of shareholders’ equity and consolidated statements of comprehensive income. Separately, net realized gains and losses on foreign currency transactions are included in Miscellaneous income (expense), net, on the consolidated statements of operations. Foreign currency transactions resulted in a net gain of $0.4 million during the year ended December 31, 2018 and net losses of $1.0 million and $0.7 million Revenue Recognition The Company generally enters into contracts with customers to provide services ranging in duration from a few months to several years. The contract terms generally provide for payments based on a fixed fee or unit-of-service arrangement. The Company accounts for revenue in accordance with ASC 606, Revenue from Contracts with Customers, which the Company adopted on January 1, 2018 using the modified retrospective implementation method. Revenue on contracts is recognized when or as the Company satisfies the contract performance obligations, at the amount that reflects the Company’s cumulative progress toward delivery of the performance obligation. This progress assessment is applied to the amount of consideration to which the Company expects to be paid for delivery of the performance obligation. The Company’s performance obligations are generally satisfied over time and related revenue is recognized as services are provided to meet these obligations. Contract Assumptions An arrangement is accounted for as a contract within the scope of ASC 606 when the Company and its customers approve the contract, are committed to perform their respective obligations, each party can identify its rights regarding the goods or services to be transferred, commercial substance is present, and it is probable that the Company will collect substantially all of the consideration to which it will be entitled in exchange for the goods or services that will be transferred to the customer. For the Company’s services to meet this criteria, contracts generally need to be written, pending regulatory hurdles required to commence work must be cleared, the study protocol must be completed, the customer must have adequate funding or reasonable path to funding to execute the contracted portion of the study, and the study must be actively moving forward. Once these criteria have been met, it is deemed that the Company and its customers are committed to perform their respective obligations. Depending on the timing of when these criteria are met, revenue recognition may vary significantly on a period over period basis. Accounting for contracts performed over a period of time involves the use of various assumptions to estimate tota l contract revenue and costs. The Company estimate s expected costs to complete a contract and recognize s contracted revenue over the life of the contract as those costs are incurred. Cost estimates are based on a detailed project budget and are developed based on many variables, including, but not limited to, the scope of the work, the complexity of the study, the participating geographic locations and the Company’s historical experience. To assist with the estimation of costs expected at completion over the life of a project, regular contract reviews are performed in which performance to date is compared to the most current estimate to complete assumptions. The reviews include an assessment of costs incurred to date compared to expectations based on budget assumptions and other circumstances specific to the project. The total estimated costs necessary to complete is updated and any revisions to the existing cost estimate results in cumulative adjustments to the amount of revenue recognized in the period in which the revisions are identified. In the case of cost estimates related to activities legally contracted as reimbursable in nature, including but not limited to investigator fee activity, these estimates also influence the Company’s assumed contract value and assumed remaining performance obligations. Because of the uncertainties inherent in estimating the costs necessary to fulfill contractual obligations, it is possible that estimates may change in the near term, resulting in a material change in revenue reported. Contracts generally provide for pricing modifications upon scope of work changes. The Company recognizes revenue, at an amount to which it expects to be entitled, related to work performed in connection with scope changes when the underlying services are performed and a binding contractual commitment has been established with the customer. If the Company’s customers do not agree to contract changes upon changes in the Company’s scope of work, the Company could be exposed to cost overruns and reduced contract profitability. Costs are not deferred in anticipation of contracts being awarded or amendments being finalized, but are expensed as incurred. Most contracts are terminable by the customer, either immediately or according to advance notice terms specified within the contracts. These contracts require payment of fees for services rendered through the date of termination and may require payment for subsequent services necessary to conclude the study or close out the contract. Final settlement amounts are agreed to with the customer based on remaining work to be performed. These amounts are included in revenue when the Company believes the amount can be estimated reliably and its realization is probable. In evaluating the probability of recognition, the Company considers the contractual basis for the settlement amount and the objective evidence available to support the amount. Certain contracts contain volume rebate arrangements with our customers that provide for rebates if certain specified spending thresholds are met. These obligations are considered as a reduction in revenue when it appears probable that the arrangement thresholds will be met, which can be at contract inception. Total revenue is presented net of rebates of $1.2 million, $0.2 million and less than $0.1 million in the consolidated statements of operations during the years ended December 31, 2018, 2017 and 2016, respectively. The Company occasionally enters into incentive fee arrangements with customers that provide for additional compensation if certain defined contractual milestones or performance thresholds are met. These additional fees are included in the estimated transaction price when there is a basis to reasonably estimate the amount of the fee and when achievement of the incentive milestone is deemed probable. These estimates are based on anticipated performance, the Company’s best judgment at the time or ultimately, upon achievement of the threshold or milestone. The Company records revenue net of any tax assessments by governmental authorities that are imposed and concurrent with specific revenue generating transactions. Performance Obligations Substantially all of the Company’s contracts consist of a single performance obligation, as the promise to transfer the individual services described in the contracts are not separately identifiable from other promises in the contracts, and therefore not distinct. Revenue recognition is determined by assessing the progress of performance completed or delivered to date compared to total services to be delivered under the terms of the arrangement. The measures utilized to assess progress on the satisfaction of performance are specific to the performance obligation identified in the contract. For the majority of the Company’s contract performance obligations, it utilizes the input method of cost to cost to measure progress, as the Company has determined that it is the most consistent measure of progress among contract tasks and represents the most faithful depiction of the transfer of services over the contract life. Under this method, the Company determines cost incurred to date for the services it provides compared to the total estimated costs at completion. For certain other contractual performance obligations, the Company has determined that an output method is the best measure of progress. These relate to certain unitized contracts, and the Company recognizes revenue in the period in which the unit is delivered compared to total contracted units. On December 31, 2018, the Company had approximately $1,060.7 million of performance obligations remaining to be performed for active projects. Concentration of Credit Risk Financial instruments that subject the Company to credit risk primarily consist of cash and cash equivalents and accounts receivable. The cash and cash equivalent balances are held and maintained with financial institutions with reputable credit ratings and, consequently, the Company believes that such funds are subject to minimal credit risk. The Company generally does not require collateral or other securities to support customer receivables. In the years ended December 31, 2018, 2017 and 2016, credit losses have been immaterial and within management’s expectations. At December 31, 2018 and 2017, there were no customers accounting for more than 10% of the Company’s accounts receivable. Costs and Expenses The Company incurs costs associated with service delivery including direct labor and related employee benefits, laboratory supplies, and other expenses. These costs are recorded in Direct service costs, excluding depreciation and amortization as a component of Total direct costs in the accompanying consolidated statements of operations. In addition, the Company incurs expenses on behalf of its customers for various project expenditures including, but not limited to, investigator site payments, travel, meetings, printing, and shipping and handling fees that are reimbursed by its customers at cost. These costs are included in Reimbursable out-of-pocket expenses as a component of Total direct costs in the accompanying consolidated statements of operations. Total direct costs are expensed as incurred and are not deferred in anticipation of contracts being awarded or finalization of changes in scope. Selling, general and administrative includes administrative payroll and related employee benefits, sales and marketing expenses, administrative travel, and other expenses not directly related to service delivery. Rent, utilities, supplies, and software license expenses are allocated between Total direct costs, and Selling, general and administrative based on the estimated contribution among service delivery and support function efforts on a percentage basis. Depreciation and amortization is reported separately in the accompanying consolidated statements of operations. Costs of sales and marketing activities not subject to recovery pursuant to customer contracts, such as feasibility assessments and negotiation of contracts, are expensed as incurred and recorded as a component of Selling, general and administrative in the accompanying consolidated statements of operations. Advertising expenses are recorded as a component of Selling, general and administrative expenses in the accompanying consolidated statements of operations. Total advertising expenses of $0.8 million, $0.6 million and $0.6 million Prior to the adoption of Accounting Standard Update No. 2014-09 ‘‘Revenue from Contracts with Customers”, fees paid to investigators and other disbursements in which the Company acts as an agent on behalf of the customer were recorded net in the consolidated statements of operations with no impact on the Company’s revenue or expenses. Funds received in advance of study expenditures were recorded as Pre-funded study cost liabilities on the consolidated balance sheets. Any pre-funded amounts remaining at the conclusion of a study were returned to the client. Pre-funded study cost disbursements of $138.7 and $150.3 million Income Taxes The Company’s consolidated U.S. federal income tax return is comprised of its U.S. subsidiaries and one of its foreign subsidiaries located in Korea. All foreign subsidiaries of the Company file tax returns in their local jurisdictions. The Company provides for income taxes on all transactions that have been recognized in the consolidated financial statements in accordance with accounting guidance governing income tax accounting. Accordingly, the impact of changes in income tax laws on deferred tax assets and deferred tax liabilities are recognized in net earnings in the period during which such changes are enacted. The Company records deferred tax assets and liabilities based on temporary differences between the financial statement bases and tax bases of assets and liabilities. Deferred tax assets are recorded for tax benefit carryforwards using tax rates anticipated to be in effect in the year in which the temporary differences are expected to reverse. If it does not appear more likely than not that the full value of a deferred tax asset will be realized, the Company records a valuation allowance against the deferred tax asset, with an offsetting charge to the Company’s income tax provision or benefit. The value of the Company’s deferred tax assets is estimated based on, among other things, the Company’s ability to generate a sufficient level of future taxable income. In estimating future taxable income, the Company has considered both positive and negative evidence, such as historical and forecasted results of operations, and has considered the implementation of prudent and feasible tax planning strategies. The Company’s current accounting position is that unremitted foreign earnings are indefinitely reinvested. Therefore, the Company has not recorded deferred foreign withholding taxes on the unremitted foreign earnings. Refer to Note 12 for further information regarding this assertion. The Company follows accounting guidance related to accounting for uncertainty in income taxes which requires significant judgment in determining what constitutes an individual tax position as well as assessing the possible outcome of each tax position. Changes in judgments as to recognition or measurement of tax positions can materially affect the estimate of the effective tax rate, and, consequently, the Company’s consolidated financial results. The Company considers many factors when evaluating and estimating tax positions and tax benefits, which may require periodic adjustments and which may not accurately anticipate actual outcomes. In addition, the calculation of tax liabilities involves dealing with uncertainties in the application of complex tax regulations in a multitude of jurisdictions. The Company determines its liability for uncertain tax positions globally. If the payment of these amounts ultimately proves to be unnecessary, the reversal of liabilities would result in tax benefits being recognized in the period when it is determined the liabilities are no longer necessary. If the calculation of the liability related to uncertain tax positions proves to be more or less than the ultimate assessment, a tax expense or tax benefit would result. Interest and penalties associated with uncertain tax positions are recognized as components of the Company’s Income tax provision. Research and Development Credits Research and development credits are available to the Company under tax laws in certain jurisdictions, based on qualifying research and development spend as defined under those tax laws. Certain tax jurisdictions provide refundable credits that are not wholly dependent on the Company’s income tax status or income tax position. In these circumstances the benefit of the credits is recorded as a reduction of operating expense. When they are wholly dependent upon the Company’s income tax position, research and development credits are recognized as a reduction of income tax expense. Stock-Based Compensation The Company has stock-based employee compensation plans for which it incurs compensation expense. Equity Awards In connection with the Company's IPO, the Board approved the formation of the 2016 Incentive Award Plan (the “2016 Plan”), which replaced our 2014 Equity Incentive Plan (the “2014 Plan”). The 2016 Plan provides for long-term equity incentive compensation for key employees, officers and non-employee directors. A variety of discretionary awards (collectively, the “Awards”) for employees and non-employee directors are authorized under the 2016 Plan, including vested common shares, stock options, stock appreciation rights (“SARs”), restricted stock awards (“RSAs”), restricted stock units (“RSUs”), or other cash based or stock dividend equivalent awards. The vesting of such awards may be conditioned upon either a specified period of time or the attainment of specific performance goals as determined by the administrator of the 2016 Plan. The option price and term are also subject to determination by the administrator with respect to each grant. Option prices are generally expected to be set at the market price of our common stock at the date of grant and option terms are not expected to exceed ten years. All outstanding Awards under the 2016 Plan are equity classified awards. The Company created the 2014 Plan, providing for the future issuance of vested shares, stock options, RSAs and RSUs in Medpace Holdings, Inc.’s common stock (the “2014 Plan Awards”). The 2014 Plan Awards were subject to either equity or liability-classification pursuant to the terms of the participant’s award agreement and the 2014 Plan based on accounting guidance which governs such transactions. Stock-based compensation expense for both the 2016 Plan and 2014 Plan is calculated using the fair value method on the grant date. The Company expenses stock-based compensation using a graded vesting schedule. For liability-classified awards under the 2014 Plan, the Company recorded fair value adjustments up to and including the settlement date. Changes in the fair value of the stock compensation liability that occurred during the requisite service period were recognized as compensation cost over the vesting period. Changes in the fair value of the stock compensation liability that occurred after the end of the requisite service period but before settlement, were compensation cost of the period in which the change occurred. As a result of the Company’s IPO, a condition of all outstanding stock options issued before August 10, 2016 under the 2014 Plan that previously required the exchange of the shares issued for incentive units in the equity of a non-consolidated related party was dissolved. All future exercises of options issued pursuant to the 2014 Plan will settle in unregistered shares of the Company. As a result of the modification in the settlement condition, the options are equity-classified instruments and changes in the fair value of the stock compensation liability that occur during the requisite service period are no longer recognized. Stock-based compensation expense is allocated between Total direct costs, and Selling, general and administrative in the consolidated statements of operations based on the underlying classification and scope of work for the employees receiving the Awards. Net Income Per Share Basic and diluted earnings or loss per share (“EPS”) are computed using the two-class method, which is an earnings allocation that determines EPS for each class of common stock and participating securities according to dividends declared and participation rights in undistributed earnings. The Company’s RSAs are considered participating securities because they are legally issued at the date of grant and holders are entitled to receive non-forfeitable dividends during the vesting term. The computation of diluted EPS includes additional common shares, such as unvested RSUs and stock options with exercise prices less than the average market price of the Company’s common stock during the period (“in-the-money options”), which would be considered outstanding under the treasury stock method. The treasury stock method assumes that additional shares would have to be issued in cases where the exercise price of stock options is less than the value of the common stock being acquired because the cash proceeds received from the stock option holder would not be sufficient to acquire that same number of shares. The Company does not compute diluted EPS in cases where the inclusion of such additional shares would be anti-dilutive in effect. The following table sets forth the computation of basic and diluted earnings per share for the years ended December 31, 2018, 2017 and 2016 (in thousands, except for earnings per share): Year Ended December 31, 2018 2017 2016 Weighted-average shares: Common shares outstanding 35,547 39,056 35,690 RSAs 142 90 88 Total weighted-average shares 35,689 39,146 35,778 Earnings per common share—Basic Net income $ 73,185 $ 39,122 $ 13,425 Less: Undistributed earnings allocated to RSAs 291 90 33 Net income available to common shareholders—Basic $ 72,894 $ 39,032 $ 13,392 Net income per common share—Basic $ 2.05 $ 1.00 $ 0.38 Basic weighted-average common shares outstanding 35,547 39,056 35,690 Effect of diluted shares 1,365 783 639 Diluted weighted-average shares outstanding 36,912 39,839 36,329 Net income per common share—Diluted $ 1.97 $ 0.98 $ 0.37 For the years ended December 31, 2018, 2017 and 2016, the computation of diluted EPS excludes the effect of (in thousands) 121, 63 and 0 stock options, respectively, due to each respective period’s average fair value of the Company’s common stock not exceeding the exercise prices. Fair Value Measurements The Company follows accounting guidance related to fair value measurements that defines fair value, establishes a framework for measuring fair value, and establishes a hierarchy for inputs used in measuring fair value. This hierarchy maximizes the use of “observable” inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. The hierarchy specifies three levels based on the inputs, as follows: Level 1: Valuations based on quoted prices in active markets for identical assets or liabilities. Level 2: Valuations based on directly observable inputs or unobservable inputs corroborated by market data. Level 3: Valuations based on unobservable inputs supported by little or no market activity representing management’s determination of assumptions of how market participants would price the assets or liabilities. The fair value of financial instruments such as cash and cash equivalents, accounts receivable and unbilled, net, accounts payable, accrued expenses, and advanced billings approximate their carrying amounts due to their short term maturities. The Company does not have any recurring fair value measurements as of December 31, 2018. There were no transfers between Level 1, Level 2, or Level 3 during the years ended December 31, 2018, 2017 and 2016. Cash and Cash Equivalents, including Restricted Cash Cash and cash equivalents, including restricted cash, are invested in demand deposits, all of which have an original maturity of three months or less. Restricted cash consists of customer funds received in advance and subject to specific restrictions, as well as amounts placed in escrow for contingent payments resulting from acquisitions or other contractual arrangements. Accounts Receivable and Unbilled, Net Accounts receivable represent amounts due from the Company’s customers who are concentrated primarily in the pharmaceutical, biotechnology, and medical device industries. Unbilled services represent revenue recognized to date that is currently not billable to the customer pursuant to contractual terms. In general, amounts become billable upon the achievement of negotiated contractual events or in accordance with predetermined payment schedules. Amounts classified to unbilled services are those billable to customers within one year from the respective balance sheet date. The Company grants credit terms to its customers prior to signing a service contract and monitors the creditworthiness of its customers on an ongoing basis. The Company maintains an allowance for doubtful accounts based on specific identification of accounts receivable that are at risk of not being collected. Uncollectible accounts receivable are written off only after all reasonable collection efforts have been exhausted. Moreover, in some cases the Company requires advance payment from its customers for a portion of the study contract price upon the signing of a service contract. These advance payments are deferred and recognized as revenue as services are performed. Inventory Inventory, which consists primarily of laboratory supplies, is valued at the lower of cost or market. Inventory is stated at purchased cost using the first-in, first out (FIFO) cost method. The inventory balance is included in Prepaid expenses and other current assets in the consolidated balance sheets. Property and Equipment Property and equipment is recorded at cost. Depreciation is provided on the straight-line method at rates adequate to allocate the cost of the applicable assets over their estimated useful lives, which is three to five years for computer hardware, software, phone, and medical imaging equipment, five to seven years for furniture and fixtures and other equipment, and thirty to forty years for buildings. The Company capitalizes costs of computer software developed for internal use and amortizes these costs on a straight-line basis over the estimated useful life, not to exceed three years. Leasehold improvements and deemed assets from landlord building construction are capitalized and amortized on a straight-line basis over the shorter of the estimated useful life of the improvement or the associated remaining lease term. Repairs and maintenance are expensed as incurred. Leases The Company leases facilities and equipment to be used in its operations, some of which require capitalization in accordance with US GAAP. Upon the execution of new leases, the Company determines the appropriate classification of the lease as operating or capital and reflects the impact of this classification in its consolidated financial statements. Goodwill and Intangible Assets Goodwill Goodwill represents the excess of purchase price over the fair value of net assets acquired in business combinations. The carrying value of goodwill is reviewed at least annually for impairment, or as indicators of potential impairment are identified, at the reporting unit level. The reporting units are Phase II-IV clinical research services, Laboratories, and Clinics as of December 31, 2018. The Company performs its annual impairment tests during the fourth quarter each year, utilizing the quantitative two step model defined by accounting guidance which governs such assessments. The first step involves the Company comparing each of its reporting unit carrying values, inclusive of assigned goodwill, to their respective estimated fair values. Fair value is estimated using a combination of the income approach, a discounted cash flow analysis, and the market approach, utilizing the guideline company method. If the calculation in the first step results in any of the reporting units’ carrying values exceeding their respective estimated fair values, a second step is performed. The second step requires the Company to allocate the fair value of the reporting unit derived in the first step to the fair value of the reporting unit’s net assets. Any fair value in excess of amounts allocated to such net assets represent the implied fair value of goodwill for that reporting unit. Any excess of reporting unit carrying value of goodwill over the implied fair value of goodwill results in an impairment. There was no indication of impairment related to goodwill based on the fourth quarter 2018 assessment. Intangible Assets The Company has an indefinite lived intangible asset related to its trade name. The carrying value of the trade name asset is reviewed at least annually for impairment, or as indicators of potential impairment are identified. The Company performs its annual impairment test in the fourth quarter each year in conjunction with its annual assessment of goodwill. The assessment consists of comparing the carrying value of the indefinite lived intangible asset to its estimated fair value, utilizing the relief from royalty method, an income approach valuation. There was no indication of impairment related to the trade name asset based on the fourth quarter 2018 assessment. Finite-lived intangible assets consist mainly of the value assigned to customer relationships, backlog and developed technologies. Finite-lived intangible assets are amortized straight-line or using an accelerated method over their estimated useful lives, which range in term from five to fifteen years. Impairment of Long-Lived Assets Long-lived assets, primarily property and equipment and finite-lived intangible assets, are reviewed for impairment and the reasonableness of the estimated useful lives whenever events or changes in circumstances indicate that the carrying amounts of the assets may not be recoverable or that a change in useful life may be appropriate. Recoverability for long-lived assets is determined by comparing the forecasted undiscounted cash flows of the operation to which the assets relate to the carrying amount of the assets. If the undiscounted cash flows are less than the carrying amount of the assets, then the Company reduces the carrying value of the assets to estimated fair values, which are primarily based upon forecasted discounted cash flows. Fair value of long-lived assets is determined based on a combination of discounted cash flows and market multiples. Advanced Billings Advanced billings represents cash received from customers, or billed amounts per an agreed upon payment schedule, in advance of services being performed or revenue being recognized. Deemed Landlord Liabilities Deemed landlord liabilities are recorded at their net present value when the Company enters into qualifying leases and are reduced as the Company makes periodic lease payments on the properties. Deferred Credit Deferred credit represents tax credits recognized initially in conjunction with the Nephrogenex asset acquisition that will be recognize

Contract Assets and Contract Li

Contract Assets and Contract Liabilities	12 Months Ended
	Dec. 31, 2018
Revenue From Contract With Customer [Abstract]
Contract Assets and Contract Liabilities	4. CONTRACT ASSETS AND CONTRACT LIABILITIES Contract assets and liabilities are reflected in the Company’s consolidated balance sheets within the accounts reflected below. Contract Assets Accounts receivable represent amounts due from the Company’s customers who are concentrated primarily in the pharmaceutical, biotechnology, and medical device industries. Unbilled represents revenue recognized to date that has not been billed or is not yet contractually billable to the customer. In general, amounts become billable upon the achievement of negotiated contractual events, in accordance with predetermined payment schedules or when a reimbursable expense has been incurred. Amounts classified to unbilled are those billable to customers within one year from the respective balance sheet date. Accounts receivable and unbilled, net consisted of the following (in thousands): As of December 31, January 1, December 31, 2018 2018 Adjustments 2017 Accounts receivable $ 85,120 $ 70,943 $ 15,344 $ 55,599 Unbilled receivables 49,361 36,696 8,543 28,153 Less: allowance for doubtful accounts (1,032 ) (673 ) - (673 ) Total accounts receivable and unbilled, net $ 133,449 $ 106,966 $ 23,887 $ 83,079 Unbilled receivables increased from $36.7 million at January 1, 2018, which includes adjustments of $8.5 million related to the adoption of ASC 606, to $49.4 million at December 31, 2018. The increase is primarily driven by revenue recognized on certain contracts in advance of customer invoicing. Contract Liabilities Advanced billings represents cash received from customers, or billed amounts per an agreed upon payment schedule, in advance of services being performed or revenue being recognized. Advanced billings consisted of the following (in thousands): As of December 31, January 1, December 31, 2018 2018 Adjustments 2017 Advanced billings $ 147,935 $ 112,613 $ 38,857 $ 73,756 Pre-funded study costs $ - $ - $ (57,406 ) $ 57,406 Advanced billings increased from $112.6 million at January 1, 2018, which includes adjustments of $38.9 million related to the adoption of ASC 606, to $147.9 million at December 31, 2018. The increase is primarily driven by billing and/or collection activity in the year ended December 31, 2018 in advance of revenue being earned for delivery of service obligations. A rollforward of allowance for doubtful account activity is as follows: Year Ended December 31, 2018 2017 2016 Allowance for doubtful accounts - beginning balance $ (673 ) $ (3,222 ) $ (1,724 ) Current year provision (791 ) (250 ) (2,166 ) Write-offs, recoveries and the effects of foreign currency exchange 432 2,799 668 Allowance for doubtful accounts - ending balance $ (1,032 ) $ (673 ) $ (3,222 )

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Property and Equipment, Net	5. PROPERTY AND EQUIPMENT, NET Property and equipment, net consisted of the following at December 31 (in thousands): 2018 2017 Land $ 1,240 $ 972 Equipment 15,437 12,171 Furniture, fixtures, and leasehold improvements 20,892 21,280 Computer hardware, software, and phone equipment 11,566 9,571 Buildings 8,145 2,559 Deemed assets from landlord building construction 22,752 22,752 Construction-in-progress 5,334 5,554 Property and equipment at cost 85,366 74,859 Less: Accumulated depreciation (33,111 ) (26,120 ) Property and equipment, net $ 52,255 $ 48,739 Depreciation expense, which includes amortization from capital leases, was $9.2 million, $8.6 million and $7.4 million for the years ended December 31, 2018, 2017 and 2016, respectively. In 2011, Medpace, Inc. entered into two multi-year lease agreements governing the future occupancy of additional office space in Cincinnati, Ohio. The Company assumed occupancy of both spaces during 2012 and began making lease payments at that time. The leases expire in 2027 and the Company has one 10-year option to extend the term of the leases. In accordance with the accounting guidance related to leases, the Company was deemed in substance to be the owner of the property during the construction phase. The accounting guidance requires that a lessee be considered the owner of a real estate project during the construction period if a related party of the lessee is an owner of the real estate. Given that a related party of Medpace made an equity investment in the lessor, Medpace was considered the owner of the property for accounting purposes during the buildings’ construction. Accordingly, the Company reflected the building and related liabilities as Deemed assets from landlord building construction (“Deemed Assets”) and Deemed landlord liabilities, respectively in the consolidated balance sheets. The Deemed Assets are being fully depreciated, on a straight line basis, over the 15-year term of the lease.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	6. GOODWILL AND INTANGIBLE ASSETS Goodwill Total assets carried on the balance sheet and not remeasured to fair value on a recurring basis, identified as Level 3 measurements, as of December 31, 2018 are $692.6 million, comprised of $661.0 million of goodwill and Intangible Assets, Net Intangible assets, net consisted of the following at December 31 (in thousands): 2018 2017 Intangible assets: Finite-lived intangible assets: Carrying amount: Backlog $ 72,630 $ 72,630 Customer relationships 145,051 145,051 Developed technologies 54,475 54,475 Other 3,074 3,074 Total finite-lived intangible assets 275,230 275,230 Accumulated amortization: Backlog (72,630 ) (72,630 ) Customer relationships (110,636 ) (92,661 ) Developed technologies (51,751 ) (40,856 ) Other (2,680 ) (1,989 ) Total accumulated amortization (237,697 ) (208,136 ) Total finite-lived intangible assets, net 37,533 67,094 Trade name (indefinite-lived) 31,646 31,646 Total intangible assets, net $ 69,179 $ 98,740 As of December 31, 2018, estimated amortization expense of the Company’s intangible assets for each of the next five years and thereafter is as follows (in thousands): 2019 $ 14,829 2020 7,876 2021 5,114 2022 3,353 2023 2,199 Later years 4,162 $ 37,533

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2018
Payables And Accruals [Abstract]
Accrued Expenses	7. ACCRUED EXPENSES Accrued expenses consisted of the following at December 31 (in thousands): 2018 2017 Employee compensation and benefits $ 31,344 $ 19,707 Project related reimbursable expenses 51,109 - Other 5,040 3,966 Total accrued expenses $ 87,493 $ 23,673

Debt

Debt	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Debt	8. DEBT Debt consisted of the following at December 31 (in thousands): 2018 2017 Revolving credit facility $ - $ 70,000 Term loan 80,438 152,625 Less unamortized discount (282 ) (399 ) Less unamortized term loan debt issuance costs (435 ) (615 ) Less current portion of long-term debt - (16,500 ) Long-term debt, net, less current portion $ 79,721 $ 205,111 Principal payments on debt are due as follows (in thousands): 2019 - 2020 - 2021 80,438 Total $ 80,438 The estimated fair value of the Company’s debt based on Level 2 inputs using the market approach, which is primarily based on rates at which the debt is traded among financial institutions, 2016 Credit Agreement On December 8, 2016 (the “Closing Date”), Medpace IntermediateCo, Inc., as borrower (the “Borrower”), and Medpace Acquisition, Inc., a wholly-owned subsidiary of Medpace Holdings, Inc. (the “Company”), as parent guarantor (the “Parent Guarantor”), entered into a credit agreement (the “Senior Secured Credit Agreement”) consisting of a $ 165.0 million term loan (the “Senior Secured Term Loan Facility”) issued at 99.7 % and a $ 150.0 million revolving credit facility (the “Senior Secured Revolving Credit Facility” and, together with the Senior Secured Term Loan Facility, the “Senior Secured Credit Facilities”). The Senior Secured Term Loan Facility and Senior Secured Revolving Credit Facility expire in December 2021 . The Senior Secured Credit Facilities provide for, at the Company’s option, interest at the Eurocurrency rate or Base rate for the Senior Secured Term Loan Facility and the Senior Secured Revolving Credit Facility borrowings. The Company, at its discretion, may choose interest periods of one, two, three or six months, which determines the interest rate to be applied. Interest on Eurocurrency loans continues to be payable at the end of the selected Eurocurrency term and interest on Base rate loans are payable quarterly in conjunction with any required principal payments. Borrowings under the Senior Secured Credit Facilities bear interest at a rate equal to, at our option, either (i) the adjusted Eurocurrency rate based on LIBOR for U.S. dollar deposits for loans denominated in dollars, EURIBOR for Euro deposits for loans denominated in Euros and the offer rate for any other currencies for loans denominated in such other currencies for the relevant interest period plus an applicable margin from 1.25% to 2.25% based on the total net leverage ratio from less than 1.50:1.00 to greater than 3.75:1:00, or (ii) an alternative base rate (determined by reference to the highest of (a) the prime commercial lending rate of the administrative agent, as established from time to time, (b) the Federal Funds Rate plus 0.50% and (c) the one-month adjusted Eurocurrency rate for loans in U.S. dollars plus 1.00%) plus an applicable margin from 0.25% to 1.25% based on the total net leverage ratio from less than 1.50:1.00 to greater than 3.75:1:00. The applicable margin as of December 31, 2018 was 1.25% for eurocurrency loans and 0.25% for base rate loans. The Company may voluntarily prepay outstanding loans under the Senior Secured Credit Facilities without premium or penalty. As of December 31, 2018, the interest rate applicable on the term loan was the Eurocurrency interest rate of 3.77%. In addition, the Company is required to pay to the lenders a commitment fee on a quarterly basis at an annual rate of 0.375% of the unused borrowings under the Senior Secured Revolving Credit Facility for the first full fiscal quarter after the closing date, and thereafter 0.50% if the total net leverage ratio is greater than or equal to 3.00:1.00, or 0.375% if the total net leverage ratio is less than 3.00:1.00. At December 31, 2018 and 2017, respectively, the Company had no outstanding borrowings and $70.0 million outstanding borrowings under the Senior Secured Revolving Credit Facility, resulting in $149.8 million and $80.0 million in undrawn capacity available under the Senior Secured Revolving Credit Facility. As of December 31, 2018, the interest rate applicable on the Senior Secured Revolving Credit Facility was the Eurocurrency interest rate of 3.77%. In addition, the Company had $0.2 million and $0.3 million in letters of credit outstanding, which are secured by the Senior Secured Revolving Credit Facility at December 31, 2018 and 2017, respectively. The original issue discount of $0.5 million related to the issuance of the Senior Secured Term Loan Facility was recorded as a reduction of the underlying debt issuances within Long-term debt, net, less current portion and is being amortized over the life of the debt using the effective-interest method. The unamortized portion of the discount related to the Senior Secured Term Loan Facility was $0.3 million and $0.4 million as of December 31, 2018 and 2017, respectively. Per the terms of the Senior Secured Credit Term Loan Facility, principal is scheduled to be paid quarterly on the last business day of March, June, September and December of each year, beginning March 2017. Origination fees of $0.8 million related to the Senior Secured Term Loan Facility were recorded as a reduction of the underlying debt issuances in Long-term debt, net. These fees are being amortized over the life of the debt using the effective-interest method. The unamortized portion of the origination fees related to the Senior Secured Term Loan Facility was $0.4 million and $0.6 million at December 31, 2018 and 2017, respectively. Origination fees of $1.6 million related to the Senior Secured Revolving Credit Facility were originally capitalized as a component of Other assets. These fees are being amortized over the life of the debt using the effective-interest method. The unamortized portion of the origination fees related to the Senior Secured Revolving Credit Facility was $0.9 million and $1.3 million at December 31, 2018 and 2017, respectively. The Senior Secured Credit Facilities are guaranteed by the Parent Guarantor and its material, direct or indirect wholly owned domestic subsidiaries, with certain exceptions, including where providing such guarantees is not permitted by law, regulation or contract or would result in adverse tax consequences. The Senior Secured Credit Facilities are subject to customary covenants relating to financial ratios and restrictions on certain types of transactions, including restricting the Company's ability to incur additional indebtedness, acquire and dispose of assets, make investments, pay dividends, or engage in mergers and acquisitions. The Company is required to maintain a ratio of consolidated funded indebtedness minus unrestricted cash and cash equivalents (in the aggregate not to exceed $ 50 million and to include not more than $ 25 million of foreign unrestricted cash and cash equivalents) to consolidated EBITDA for the most recent four fiscal quarter period not to exceed 4.00 :1.00; provided that the Company shall be permitted to increase the ratio to 4.50 :1.00 in connection with any permitted acquisition or any other acquisition consented to by the Administrative Agent and the Required Lenders (as defined in the Senior Secured Credit Agreement) with total cash consideration in excess of $ 25 million. Such increase shall be applicable for the fiscal quarter in which such acquisition is consummated and the three consecutive test periods thereafter. The Company is also required to maintain a ratio of consolidated EBITDA to consolidated interest expense, in each case for the most recent four fiscal quarter period, of not less than 3.00 :1.00. The Company was in compliance with all financial covenants as of December 31, 2018 . Borrowings under the Senior Secured Credit Facilities were utilized to repay and extinguish our obligations under the 2014 Senior Secured Credit Facilities, as defined in Note 8 of the 2017 Annual Report on Form 10-K. In accordance with accounting guidance governing such transactions, upon closing the 2014 Senior Secured Credit Facility and commencement of the Senior Secured Credit Facilities, the Company recognized a loss on extinguishment of debt totaling $10.7 million, of which $10.2 million related to unamortized loan origination fees from the credit agreement for our 2014 Senior Secured Credit Facilities and $0.5 million related to third party fees incurred during the fourth quarter of 2016.

Commitments, Contingencies, and

Commitments, Contingencies, and Guarantees	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments, Contingencies, and Guarantees	9. COMMITMENTS, CONTINGENCIES, AND GUARANTEES Lease Obligations The Company has payment obligations under non-cancellable operating leases, primarily for office space and furniture and fixtures to support its global operations. These leases often contain customary scheduled rent increases or escalation clauses and renewal options. Rent expense is recorded on a straight line basis. As of December 31, 2018, minimum future lease payments required under these leases are as follows (in thousands): Non-Related Total Related Party Parties Operating Operating Operating Leases Leases Leases 2019 $ 1,987 $ 6,186 $ 8,173 2020 6,843 6,617 13,460 2021 6,964 5,873 12,837 2022 6,757 3,694 10,451 2023 5,229 3,257 8,486 Thereafter 103,870 5,752 109,622 Total minimum lease payments $ 131,650 $ 31,379 $ 163,029 The related party operating leases are for two of the Company’s several buildings within its corporate headquarters. The non-related party operating leases are for the Company’s remaining leases throughout the world consisting primarily of office space, fixtures and vehicles. Rental expense under operating leases totaled $9.2 million, $7.9 million and $6.7 million for the years ended December 31, 2018, 2017 and 2016, respectively, and is allocated between Total direct costs, and Selling, general and administrative in the consolidated statements of operations. Deemed Landlord Liabilities As of December 31, 2018, minimum annual payments required in conjunction with the Deemed landlord liabilities are as follows (in thousands): Related Party Total Minimum Lease Less: Principal Payments Interest Amounts Due 2019 $ 3,918 $ 1,818 $ 2,100 2020 3,988 1,662 2,326 2021 4,039 1,490 2,549 2022 4,092 1,301 2,791 2023 4,145 1,095 3,050 Thereafter 15,697 1,929 13,768 Total $ 35,879 $ 9,295 $ 26,584 Legal Proceedings Medpace periodically becomes involved in various claims and lawsuits that are incidental to its business. Management believes, after consultation with counsel, that no matters currently pending would, in the event of an adverse outcome, have a material impact on the Company’s consolidated balance sheets, statements of operations, or cash flows for the years ended December 31, 2018, 2017 and 2016. Purchase Commitments The Company has several minimum purchase commitments for project related supplies totaling $5.2 million. In return for the commitment, Medpace receives preferential pricing. The commitments expire at various times through 2023.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Shareholders' Equity	10. SHAREHOLDERS’ EQUITY Stock-Based Compensation 2016 Incentive Award Plan On August 11, 2016 in connection with the Company's IPO, the Board approved the formation of the 2016 Incentive Award Plan (the “2016 Plan”), which replaced our 2014 Equity Incentive Plan (the “2014 Plan”). The 2016 Plan provides for long-term equity incentive compensation for key employees, officers and non-employee directors. A variety of discretionary awards (collectively, the “Awards”) for employees and non-employee directors are authorized under the 2016 Plan, including vested shares, stock options, stock appreciation rights (“SARs”), restricted stock awards (“RSAs”), restricted stock units (“RSUs”), or other cash based or stock dividend equivalent awards, which are all equity-classified instruments under the 2016 Plan. The number of shares registered and available for grant under the 2016 Plan is 6,000,000. The vesting of such awards may be conditioned upon either a specified period of time or the attainment of specific performance goals as determined by the administrator of the 2016 Plan. The option price and term are also subject to determination by the administrator with respect to each grant. Option prices are generally expected to be set at the market price of the Company’s common stock at the date of grant and option terms are not expected to exceed ten years. The Company granted 850,700 awards to employees under the 2016 Plan during the year ended December 31, 2018, consisting of 550,500 stock option awards and 300,200 restricted stock units (“RSU”), all vesting after four years. The Company granted an additional 33,801 stock option awards to non-employee directors under the 2016 Incentive Award Plan, during the year ended December 31, 2018. These awards will vest on the earlier of (a) the day immediately preceding the date of the first annual meeting following the date of grant and (b) the first anniversary of the date of grant, subject to the non-employee director continuing in service through the applicable vesting date. The Company granted awards to employees under the 2016 Plan during the year ended December 31, 2017, consisting of 797,550 stock option awards, 118,000 restricted stock awards (“RSA”) and 38,000 restricted stock units (“RSU”), all vesting after four years . The Company granted 15,000 stock option awards, vesting equally on the second, third and fourth anniversary of the grant date over four years . Additionally, the Company granted 41,346 stock option awards, vesting over one year , to non-employee directors under the 2016 Incentive Award Plan, during the year ended December 31, 2017. The Company granted 648,180 stock options under the 2016 Plan during the year ended December 31, 2016, consisting of 626,650 stock options vesting after four years and 21,530 stock options with various vesting schedules, but all of which vest within a calendar year of the respective grant date. The 2016 Plan has reserved 6,000,000 shares for issuance of RSAs, RSUs or stock options, of which approximately 3.8 million awards were available for future grants as of December 31, 2018. The 2016 Plan expires in 2026, except for awards then outstanding, and is administered by the Board. All Awards granted at the IPO or thereafter were or will be issued under the 2016 Plan. The company satisfies stock option exercises and vested stock awards with newly issued shares. Shares available for future stock compensation grants totaled 3.8 million and 4.3 million at December 31, 2018 and 2017. 2014 Equity Incentive Plan The 2014 Plan for employees and directors provided the issuance of vested shares, stock options, RSAs and RSUs in Medpace Holdings, Inc.’s common stock. The awards were granted to key employees as additional compensation for services rendered and as a means of retention over the vesting period, typically three to four years. RSAs awarded under the 2014 Plan were subject to automatic forfeiture upon departure until vested and entitle the shareholder to all rights of common stock ownership except that they may not be sold, transferred, pledged or otherwise disposed of during the restriction period, except as noted in the following paragraph. The 2014 Plan allowed for the issuance of non-qualified stock options to employees, officers, and directors under this plan (collectively, “the Participants”). Under the 2014 Plan, options could be granted with an exercise price equal to or greater than the fair value of common stock at the grant date as determined by the Board of Directors. The stock options, if unexercised, expired seven years from the date of grant. As a condition to exercising stock options and acceptance of certain restricted shares, employees must have executed a Contribution and Subscription Agreement (the “Subscription Agreement”) that provided for the exchange of the shares issued for incentive units (the “Incentive Units”) in Medpace Investors upon the occurrence of certain events. The Incentive Units were tied directly to common stock ownership in Medpace Holdings, Inc. and entitled the Incentive Unit holder to participate in the risks and rewards of owning the Company’s stock through ownership in Medpace Investors. The awards containing this condition were liability-classified instruments as they were inevitably settled in the equity of a non-consolidated related party. Restricted share awards excluding the requirement to execute a Contribution and Subscription Agreement and settlement in common shares of Medpace Holdings, Inc. were equity-classified instruments. At the grant date for RSAs that were liability-classified, restricted shares were legally issued and exchanged for Medpace Investors Incentive Units on behalf of the employee. If the RSAs were not yet vested and an employee left the Company’s employment, the restricted shares of Medpace Holdings, Inc. reverted back to the Company and were available for re-issuance under the 2014 Plan. Upon the vesting of RSAs and RSUs and upon the exercise of stock options, the stock-based compensation liability was settled by exchanging the Company’s stock for Medpace Investors Incentive Units. If an employee left the Company’s employment after they vested in the Awards and the exchange for Incentive Units was made, Medpace Investors may exercise a call option to repurchase an employee’s Incentive Units at a price determined by the manager and majority unit holder of Medpace Investors, who is also the chief executive officer of Medpace. If Medpace Investors exercised the call right, it could do so up to the later of twelve months following the employee’s departure date or six months following the determination that the former employee was directly or indirectly engaged in competitive business activities. Restricted Awards Modification On December 17, 2015, the Board of Directors approved a resolution to accelerate the vesting period for all issued, outstanding and unvested RSAs and RSUs to vest on December 31, 2015, so long as the recipient of each restricted share or unit was in good standing, had not provided notice of resignation and continued to be employed by the Company as of December 31, 2015. In total, 688,599 unvested restricted awards held by 158 current employees were modified resulting in settlement of 688,599 shares. According to the authoritative guidance for stock-based compensation, under these circumstances a company should recognize additional stock-based compensation expense in the amount of the incremental fair value of the modified award. Because the restricted awards that were modified were liability-classified, the awards were at fair value at the time of the modification and no incremental cost was recognized. While there was no incremental cost related to fair value of the awards, $5.7 million of stock-based compensation expense was recorded in 2015 related to previously unrecognized stock-based compensation cost for awards expected to vest in 2016, 2017 and 2018. Option Awards Modification As a result of the Company’s IPO, a condition of all outstanding stock options issued before August 10, 2016 under the 2014 Plan that previously required the exchange of the shares issued for incentive units in the equity of a non-consolidated related party was dissolved. All future exercises of options issued pursuant to the 2014 Plan will now settle in shares of the Company. As a result of the modification in the settlement condition, the options will now be equity-classified instruments and changes in the fair value of the stock compensation liability that occur during the requisite service period are no longer recognized. According to the authoritative guidance for stock-based compensation, at modification the Company should recognize additional stock-based compensation expense in the amount of the incremental fair value of the modified award. As a result, the Company recognized $3.1 million of incremental stock-based compensation expense during the year ended December 31, 2016. In addition, the $10.5 million stock-based compensation liability associated with the modified stock options was reclassified to additional paid-in capital as a result of the change to equity classification. There is no stock-based compensation liability for the years ended December 31, 2018 and 2017. Equity Awards Valuation Assumptions The Company determines the fair value of stock options using the Black-Scholes-Merten option pricing model (the “BSM Model”). The BSM Model is primarily affected by the fair value of the Company’s common stock (see restricted share valuation discussion below), the expected holding period for the option, expected stock price volatility over the term of the awards, the risk-free interest rate, and expected dividends. The following table sets forth the key weighted-average assumptions used in the BSM Model to calculate the fair value of options: Year Ended December 31, 2018 2017 2016 Expected holding period - years 5.4 5.4 3.6 Expected volatility 27.0% 28.0% 30.2% Risk-free interest rate 2.8% 2.0% 1.0% Expected dividend yield 0.0% 0.0% 0.0% The assumptions used in the table above reflect both grant date inputs to arrive at the grant date fair values for stock options subject to equity-classified stock compensation accounting and reflect a fair value calculation for stock options outstanding in the period subject to liability-classified stock compensation accounting. Subsequent to August 10, 2016, The expected holding period represents the period of time the grants are expected to be outstanding. The Company uses the simplified method, as prescribed by accounting guidance governing such awards, to calculate the expected holding period for options granted to employees as we do not have sufficient historical evidence data to provide a reasonable basis upon which to estimate the expected holding period. For options valued by the Company for the years ended December 31, 2018 , 201 7 and 201 6 , the expected holding period is based on an average between the midpoint of the vesting date and the expiration date of the options. The Company estimates expected volatility primarily by using the historical volatility of a publicly traded peer group that operates in the clinical research and development industry. The Company does not have adequate history to calculate its own historical or implied volatility and believes the Company’s expected volatility will approximate the historical experience of the peer group. The risk-free interest rate is based on the yield on U.S. Treasury obligations with remaining durations equal to the expected holding period of the options. The expected dividend yield is assumed to be zero based on recent and anticipated dividend activity. Subsequent to the IPO, the fair value of common stock is based upon the market price of the Company’s common stock on the date of grant as listed on the NASDAQ. Due to the absence of an active market for the Company’s common stock prior to the IPO, the Company determined the fair value of restricted shares by obtaining an independent valuation of the fair value of the Company’s equity, applying a discount for lack of marketability, and then calculating the implied share price. The fair value of the Company was estimated primarily using an income approach which is based on assumptions and estimates made by management and, secondarily, using other market-related factors in current industry trends as well as observed transaction values. In determining the estimated future cash flows used in the income approach, the Company developed and applied certain estimates and judgments, including current and projected future levels of income based on management’s plans, business trends, prospects and market and economic conditions, including market-participant considerations. Significant assumptions utilized in the income approach were based on company specific information and projections, which were not observable in the market and are thus considered Level 3 measurements by authoritative guidance. The discount for lack of marketability (the “Marketability Discount”) was applied to reflect what a market participant would consider in relation to the post-vesting restrictions imposed regarding the inability to sell, transfer, or pledge the shares during the restriction period. The Marketability Discount was estimated by using the BSM Model to calculate the cost of a theoretical put option to hedge the fluctuation in value of the investment between the valuation date and an anticipated liquidity date. The following table summarizes the grant date fair values of stock options and restricted shares issued during the period as well as the allocation of stock-based compensation expense to Total direct costs, and Selling, general and administrative reported in the consolidated statements of operations: Year Ended December 31, 2018 2017 2016 Weighted average, grant date fair value Stock options $ 11.51 $ 8.54 $ 6.91 Restricted shares (RSAs and RSUs) $ 49.38 $ 31.90 $ 15.08 Stock-based compensation expense allocated to: Total direct costs $ 4,132 $ 2,128 $ 5,555 Selling, general, and administrative 2,367 2,335 4,260 Total stock-based compensation expense $ 6,499 $ 4,463 $ 9,815 Award Activity The following table sets forth the Company’s stock option activity: Year Ended December 31, 2018 2017 2016 Weighted Weighted Weighted Average Options Exercise Price Options Exercise Price Shares Exercise Price Outstanding - beginning of Period 2,782,868 $ 20.73 2,350,166 $ 17.57 1,794,709 $ 15.42 Granted 584,301 $ 37.72 853,896 $ 28.67 683,001 $ 22.80 Exercised (169,771 ) $ 14.98 (116,787 ) $ 15.52 (36,980 ) $ 14.50 Forfeited/Expired (252,358 ) $ 23.69 (304,407 ) $ 20.55 (90,564 ) $ 15.85 Outstanding - end of period 2,945,040 $ 24.18 2,782,868 $ 20.73 2,350,166 $ 17.57 Exercisable - end of period 1,096,116 $ 16.01 917,592 $ 15.40 647,343 $ 15.22 The following table sets forth the Company’s Restricted Share activity: Year Ended December 31, 2018 2017 2016 Shares/Units Shares/Units Shares/Units Outstanding and unvested - beginning of period 183,629 59,258 90,697 Granted 300,200 156,000 11,111 Vested (29,629 ) (29,629 ) (41,069 ) Forfeited (33,000 ) (2,000 ) (1,481 ) Outstanding and unvested - end of period 421,200 183,629 59,258 Cumulative vested shares - end of period 1,913,916 1,884,287 1,854,658 During the year ended December 31, 2016, 11,111 Restricted Shares were granted and immediately vested upon issuance (the “Vested Shares”). The following table summarizes information about stock options expected to vest, stock options exercisable, and unvested restricted share awards expected to vest at December 31, 2018: Weighted Average Weighted Average Exercise Stock Restricted Remaining Price Options Shares Life (Years) December 31, 2018 Number of stock options expected to vest $ 24.18 2,945,040 - 4.4 Number of Restricted Shares expected to vest - 421,200 Total expected to vest - December 31, 2018 2,945,040 421,200 Total stock options exercisable - December 31, 2018 $ 16.01 1,096,116 3.0 Unrecognized compensation cost - December 31, 2018 (in thousands) $ 10,021 $ 15,734 Weighted average years over which unrecognized compensation cost will be recognized 2.7 3.5 The following table sets forth the aggregate intrinsic value of stock options exercised, the fair values of awards vested, and share based liabilities settled during the respective periods (in thousands): Year Ended December 31, 2018 2017 2016 Total intrinsic value of stock options exercised $ 5,326 $ 1,619 $ 403 Total grant-date fair value of stock options vested $ 1,417 $ 1,317 $ 1,384 Total grant-date fair value of restricted shares vested $ 447 $ 447 $ 614 Total settlement date fair value of restricted shares vested $ 1,568 $ 1,074 $ 1,236 Total share-based liabilities settled $ - $ - $ 76 The actual tax benefits recognized related to stock-based compensation totaled $1.0 million, $0.5 million and $1.0 million for the years ended December 31, 2018, 2017 and 2016, respectively.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2018
Compensation Related Costs [Abstract]
Employee Benefit Plans	11. EMPLOYEE BENEFIT PLANS The Company provides a 401(k) plan that covers substantially all U.S. employees. Participants can elect to contribute up to 50% of their eligible earnings on a pre-tax basis, subject to Internal Revenue Service annual limitations. The U.S.-based plan offers a year-end employer matching contribution, requiring the participant to be an employee at year-end to qualify for the match. Participants with one year or more of service are eligible for the matching contribution. Participants fully vest in the employer contributions after three years of service. The employer contribution represents a percentage of a participant’s eligible compensation. The Company’s 401(k) Plan costs were $2.7 million, $2.3 million and $2.0 million during the years ended December 31, 2018, 2017 and 2016, respectively, and were allocated between Total direct costs, and Selling, general and administrative in the consolidated statements of operations. The Company has various defined contribution arrangements for eligible employees of non-U.S. entities. These defined contribution arrangements provide employees with retirement savings and life insurance benefits. The Company incurred expenses related to these arrangements of $1.0 million, $0.9 million and $0.7 million in the years ended December 31, 2018, 2017 and 2016, respectively, and were allocated between Total direct costs, and Selling, general and administrative in the consolidated statements of operations. The Company is also required to pay certain minimum statutory post-employment benefits. The Company recognizes a liability and the associated expense for these benefits when it is probable that employees are entitled to the benefit.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	12. INCOME TAXES US Tax Reform The “Tax Cuts and Jobs Act” (TCJA) was enacted on December 22, 2017 and it significantly reforms the Internal Revenue Code of 1986, as amended. The TCJA, among other things, includes a reduction in the U.S. federal tax rate from 35% to 21%, allows for the expensing of capital expenditures, requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred, creates new taxes on certain foreign sourced earnings and puts into effect the migration from a “worldwide” system of taxation to a territorial system. The Company recognized the income tax effects of the “Tax Cuts and Jobs Act” (TCJA) in its audited consolidated financial statements on our 2017 Annual Report on Form 10-K in accordance with Staff Accounting Bulletin No. 118, which provides Securities and Exchange Commission staff guidance for the application of ASC Topic 740, Income Taxes, in the reporting period in which the TCJA was signed into law. The guidance also provides for a measurement period of up to one year from the enactment date for the Company to complete the accounting for the U.S. tax law changes. As such, the Company’s 2017 financial results reflected the provisional estimate of the income tax effects of the TCJA. The Company completed its analysis of the TCJA in 2018 and adjusted the 2017 provisional estimates to the final amounts. A summary of the provisional and final amounts is included below: • Transition tax on unrepatriated foreign earnings: The Company originally estimated a transition tax expense of $0.6 million and the final transition tax liability is $0.7 million. The adjustment unfavorably impacted the effective tax rate by approximately 0.1%. • Reduction of U.S. Federal Corporate Tax Rate: The Company originally estimated a provisional tax benefit of $3.4 million related to the revaluation of deferred tax assets and liabilities. The deferred tax assets/liabilities as of December 31, 2017 were adjusted to match the balances per the 2017 U.S. corporate income tax return. The revised deferred balance was then adjusted from a 35% tax rate to a 21% tax rate. This resulted in a final tax benefit of approximately $3.6 million. The adjustment favorably impacted the effective tax rate by approximately 0.2%. • Indefinite reinvestment assertion: Prior to the passage of the TCJA, the Company asserted that all of the undistributed foreign earnings of its foreign subsidiaries were considered indefinitely reinvested and accordingly, no deferred taxes were provided. Beginning in 2018, the TCJA provides a 100% deduction for dividends received from 10-percent owned foreign corporations by U.S. corporate shareholders, subject to a one-year holding period. Although dividend income is now exempt from U.S. federal tax in the hands of the U.S. corporate shareholders, companies must still apply the guidance of ASC 740-30-25-18 to account for the tax consequences of outside basis differences and other tax impacts of their investments in non-U.S. subsidiaries. The Company has accrued the Transition Tax on the deemed repatriated earnings that were previously indefinitely reinvested. The Company has not recorded deferred foreign withholding taxes on approximately $21.1 million of pre-2018 earnings which are considered permanently reinvested. • Global intangible low taxed income (GILTI): The TCJA creates a new requirement that certain income (i.e., GILTI) earned by foreign subsidiaries must be included currently in the gross income of the U.S. shareholder. The Company has made an accounting policy election to treat GILTI taxes as a current period expense. The Company files income tax returns for U.S. federal and various U.S. states, as well as various foreign jurisdictions. The liabilities for unrecognized tax benefits are carried in Other long-term liabilities on the consolidated balance sheets because the payment of cash is not anticipated within one year of the balance sheet date. The components of income before income taxes consisted of the following (in thousands): Year Ended December 31, 2018 2017 2016 Domestic $ 88,014 $ 52,986 $ 18,016 Foreign jurisdictions $ 5,937 $ 3,959 $ 3,941 Income before income taxes $ 93,951 $ 56,945 $ 21,957 Income tax provision consisted of the following (in thousands): Current Deferred Total Year ended December 31, 2018 U.S. Federal $ 13,372 $ 4,172 $ 17,544 U.S. state and local 1,912 (116 ) 1,796 Foreign jurisdictions 1,408 18 1,426 $ 16,692 $ 4,074 $ 20,766 Year ended December 31, 2017 U.S. Federal $ 10,953 $ 3,466 $ 14,419 U.S. state and local 2,032 51 2,083 Foreign jurisdictions 1,576 (255 ) 1,321 $ 14,561 $ 3,262 $ 17,823 Year ended December 31, 2016 U.S. Federal $ 15,105 $ (8,784 ) $ 6,321 U.S. state and local 1,636 (524 ) 1,112 Foreign jurisdictions 710 389 1,099 $ 17,451 $ (8,919 ) $ 8,532 The difference between the statutory rate for federal income tax and the effective income tax rate was as follows (in thousands): Year Ended December 31, 2018 2017 2016 Income tax expense calculated at the federal statutory rate $ 19,730 21.0 % $ 19,931 35.0 % $ 7,685 35.0 % Effect of: State and local taxes, net of federal benefit 1,978 2.1 1,606 2.8 912 4.2 Tax on foreign earnings, net of tax credits and deductions 172 0.2 (69 ) (0.1 ) (26 ) (0.1 ) Tax reform adjustment (195 ) (0.2 ) (3,418 ) (6.0 ) - - Write off of Deferred Tax Assets 509 0.6 - - - - Deferred credit (802 ) (0.9 ) (1,053 ) (1.9 ) - - Change in valuation allowance - - - - - - Permanent items: Stock-based awards (651 ) (0.7 ) (179 ) (0.3 ) (534 ) (2.4 ) Tax reform adjustment 126 0.1 574 1.0 - - Other 687 0.7 483 0.9 174 0.8 State/Local tax credits (1,253 ) (1.3 ) (1,187 ) (2.1 ) (1,049 ) (4.8 ) Foreign tax credits (727 ) (0.8 ) - - - - Change in liability for uncertain tax positions 1,102 1.2 1,141 2.0 1,212 5.5 Other 90 0.1 (6 ) (0.0 ) 158 0.7 $ 20,766 22.1 % $ 17,823 31.3 % $ 8,532 38.9 % Components of the Company’s net deferred tax asset (liability) included in the consolidated balance sheets consisted of the following at December 31 (in thousands): 2018 2017 Deferred tax assets: Accrued liabilities $ 18,670 $ 17,563 Depreciation and amortization 872 980 Foreign operating loss carryforward 248 246 U.S. federal tax credits and carryforward - 8,152 U.S. state and local tax credits and carryforward 223 1,799 Other 41 667 Valuation allowance (169 ) (2,394 ) Total deferred tax assets 19,885 27,013 Deferred tax liabilities: Depreciation and amortization (18,803 ) (20,117 ) Prepaid expenses (550 ) (572 ) Other (258 ) (541 ) Total deferred tax liabilities (19,611 ) (21,230 ) Net deferred tax asset $ 274 $ 5,783 U.S. state and local tax credits noted above will expire in 2023 if not utilized. The Company has foreign operating loss carryforwards for which a deferred tax asset of $0.2 million has been established. The Company has a valuation allowance of $0.2 million against this deferred tax asset based upon its assessment that it is more likely than not that this amount will not be realized. The ultimate realization of this tax benefit is dependent upon the generation of sufficient operating income in the respective tax jurisdictions. Approximately 59% of the foreign net operating loss carryforwards can be utilized over an indefinite period whereas the remainder will expire at various times from 2020 to 2027 if not utilized. In May 2017, the Company acquired Nephrogenex which included deferred tax assets of $22.2 million, consisting of tax effected net operating losses in the amount of $13.5 million, tax effected capitalized research and development expenses of $8.5 million and tax effected federal tax credits of $0.2 million, and deferred tax liabilities of $0.1 million. See Note 2 for further description of the asset acquisition that occurred in the second quarter of 2017. In 2018, the Company disposed of approximately $7.4 million in deferred tax assets and reduced the Deferred credit by approximately $6.9 million (net increase in tax expense of approximately $0.5 million) as a result of an IRC Section 382 ownership shift that occurred as a result of Cinven’s sales of the Company’s securities. The ownership shift resulted in a limitation in the ability to utilize the acquired tax attributes and resulted in the described asset write-off and reduction of the Deferred credit. Annual activity related to the Company’s valuation allowance is as follows (in thousands): Year Ended December 31, 2018 2017 2016 Beginning Balance $ 2,394 $ 987 $ 1,021 Additions charged to expense - - - Additions due to asset acquisition - 2,033 - Reductions from utilization, reassessments and expirations (2,225 ) 3 (34 ) Remeasurement due to effect of tax reform - (629 ) - Ending Balance $ 169 $ 2,394 $ 987 A reconciliation of the beginning and ending balances of the total amounts of gross unrecognized tax benefits is as follows (in thousands): Year Ended December 31, 2018 2017 2016 Beginning Balance $ 6,890 $ 5,698 $ 2,604 Increases in tax positions for prior years - 5 - Decreases in tax positions for prior years (579 ) - (196 ) Increases in tax positions for current year 2,214 1,187 3,365 Lapse in statute of limitations - - (75 ) Ending Balance $ 8,525 $ 6,890 $ 5,698 Interest and penalties associated with uncertain tax positions are recognized as components of Income tax provision in the consolidated statements of operations. There was no material change to tax-related interest and penalties during the years ended December 31, 2018, 2017 and 2016. As of December 31, 2018 and 2017, respectively, the Company has a liability for interest and penalties of $1.0 million and $1.4 million that is associated with related tax liabilities of $7.2 million and $5.9 million for uncertain tax positions. The Company operates in various foreign, state and local jurisdictions. The number of tax years for which the statute of limitations remains open for foreign, state and local jurisdictions varies by jurisdiction and is approximately four years (2014 through 2018). For federal tax purposes, the Company’s open tax years are 2015 through 2018.

Miscellaneous Income (Expense),

Miscellaneous Income (Expense), Net	12 Months Ended
	Dec. 31, 2018
Other Income And Expenses [Abstract]
Miscellaneous Income (Expense), Net	13. MISCELLANEOUS INCOME (EXPENSE), NET Miscellaneous income (expense), net consisted of the following (in thousands): Year Ended December 31, 2018 2017 2016 Net gain (loss) on foreign-currency transactions $ 386 $ (1,004 ) $ (660 ) Other income 674 650 237 Miscellaneous income (expense), net $ 1,060 $ (354 ) $ (423 )

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	14. RELATED PARTY TRANSACTIONS Employee Loans The Company periodically extends short term loans or advances to employees, typically upon commencement of employment. Total receivables as a result of these employee advances of $0.2 million and 201 7 , respectively, and are included in the Prepaid expenses and other current assets and Other assets line items of the consolidated balance sheets, respectively, depending on the contractual repayment date. Management Fees In conjunction with the IPO, the Advisory Services Agreement with Cinven Capital Management (V) General Partner Limited (“Cinven”) expired. Subsequent to the IPO, the Company paid fees for director services provided by Cinven employees that were members of the Company’s Board of Directors and any related committees. The director fees were paid directly to Cinven in accordance with the Company’s non-employee director compensation policy. During the third quarter of 2018, Cinven sold its remaining shares of the Company’s common stock and all three members of the Company’s Board affiliated with Cinven subsequently resigned. During the year ended December 31, 2016, the Company incurred management fees to Cinven of $0.2 million. During the years ended December 31, 2018 and 2017, the Company incurred director fees of Service Agreements Coherus BioSciences, Inc. (“Coherus”) and MX II Associates, LLC (“MXII”) The chief executive officer of the Company was a member of Coherus BioSciences, Inc.’s (“Coherus”) board of directors until his resignation in the first quarter of 2018. Coherus is no longer considered a related party as of the first quarter of 2018. During 2011 a related party of the Company in which the Company’s chief executive officer is the managing member, MXII, made an investment in Coherus. In early 2012 the Company made a $2.5 million investment in Coherus. Concurrent with the initial investment, MXII secured the exclusive rights for Medpace to perform Phase I through Phase III clinical trial work for certain Coherus’ “bio-similar” drug compounds executed through a MSA. During the years ended December 31, 2017 and 2016, the Company recognized service revenue of $8.0 million and $22.3 million from Coherus in the Company’s consolidated statements of operations, respectively. In addition, the company recognized Reimbursed out-of-pocket revenue and Reimbursed out-of-pocket expenses with Coherus in the consolidated statements of operations of $1.3 million and $5.1 million during the years ended December 31, 2017 and 2016, respectively. . Xenon Pharmaceuticals, Inc. (“Xenon”) Certain executives and employees of the Company, including the chief executive officer, have held equity investments in Xenon, a clinical-stage biopharmaceutical company. In addition, a Medpace employee was a director of Xenon until May 2015. During the second quarter of 2017, the chief executive officer sold his entire equity position held in Xenon. Xenon is no longer considered to be a related party subsequent to this sale. During July 2015 the Company and Xenon entered into an amended MSA agreement for the Company to provide clinical trial related services. The Company recognized service revenue from Xenon of $0.6 million and $1.3 million during the six months ended June 30, 2017 and the year ended December 31, 2016, respectively, in the Company’s consolidated statements of operations. In addition, the Company recognized Reimbursed out-of-pocket revenue and Reimbursed out-of-pocket expenses with Xenon in the consolidated statements of operations of $0.1 million and $0.2 million during the six months ended June 30, 2017 and the year ended December 31, 2016, respectively. Cymabay Therapeutics, Inc. (“Cymabay”) Cymabay is a clinical-stage biopharmaceutical company developing therapies to treat metabolic diseases with high unmet medical need, including serious rare and orphan disorders. During the first quarter of 2016, it was announced that a Medpace employee would join Cymabay’s board of directors. The Company and Cymabay entered into a MSA dated October 21, 2016. Subsequently, the Company and Cymabay have entered into several task orders for the Company to perform clinical trial related services. The Company recognized total revenue from Cymabay of $10.8 million during the year ended December 31, 2018 in the Company’s consolidated statements of operations. The Company recognized service revenue from Cymabay of $0.6 million and $0.3 million during the years ended December 31, 2017 and 2016, respectively, in the Company’s consolidated statements of operations. As of December 31, 201 8 and 201 7 , the Company had Accounts receivable and unbilled, net from Cymabay of $ 2.5 million and $ 0.1 million recorded in the consolidated balance sheets, respectively. LIB Therapeutics LLC and subsidiaries (“LIB”) Certain executives and employees of the Company, including the chief executive officer, are members of LIB’s board of managers and/or have equity investments in LIB. The Company entered into a MSA dated November 24, 2015 with LIB, a company that engages in research, development, marketing and commercialization of pharmaceutical drugs. Subsequently, the Company and LIB have entered into several task orders for the Company to perform clinical trial related services. The Company recognized total revenue from LIB of $3.7 million during the year ended December 31, 2018 in the Company’s consolidated statement of operations. The Company recognized service revenue from LIB of $1.4 million and $0.2 million during the years ended December 31, 2017 and 2016 in the Company’s consolidated statements of operations, respectively. As of December 31, 2018 and 2017, the Company had, from LIB, Advanced billings of $0.3 million and $0.2 million in the consolidated balance sheets, respectively. In addition, the Company had Accounts receivable and unbilled, net from LIB of $1.0 million and $0.5 million in the consolidated balance sheets at December 31, 2018 and 2017, respectively. CinRX Pharma and subsidiaries (“CinRx”) Certain executives and employees of the Company, including the chief executive officer, are members of CinRx’s board of managers and/or have equity investments in CinRx, a biotech company. The Company and CinRx have entered into several task orders for the Company to perform clinical trial related services. During the year ended December 31, 2018, the Company recognized total revenue from CinRx of $0.5 million in the Company’s consolidated statements of operations. During the year ended December 31, 2017, the Company recognized service revenue from CinRx of $0.4 million in the Company’s consolidated statements of operations. As of December 31, 2018 the Company had Accounts receivable and unbilled, net from CinRx of $0.4 million in the consolidated balance sheets. The Summit, a Dolce Hotel (“The Summit”) The Summit Hotel, located on the Medpace campus, is owned by the chief executive officer, and managed by an unrelated hospitality management entity. Medpace incurs travel lodging and meeting expenses at The Summit. During the year ended December 31, 2018, Medpace incurred expenses of $0.4 million at The Summit. Medpace Investors, LLC Medpace Investors is a noncontrolling shareholder and related party of Medpace Holdings, Inc. Medpace Investors is owned and managed by employees of the Company. The Company’s chief executive officer is also the manager and majority unit holder of Medpace Investors. The Company acts as a paying agent for Medpace Investors with taxing authorities principally in instances when employee tax payments or remittance of withholdings related to equity compensation are required. During the year ended December 31, 2016, the Company paid $0.8 million to various taxing authorities on behalf of Medpace Investors. During the year ended December 31, 2016, the Company received $0.3 million from Medpace Investors for receivables owed to the Company from Symplmed. Additionally, during the year ended December 31, 2016, the Company paid approximately $0.3 million to Medpace Investors due to the settlement of certain liabilities related to the Merger Agreement between the sellers (led by CCMP) and the buyers (led by Cinven). Purchase of Real Estate Properties In December 2016, the Company entered into a purchase agreement for four parcels of real estate property that are closely situated to the Medpace campus in Cincinnati, Ohio, from AT Redevelopment Company, LLC, which is wholly-owned by the Company’s chief executive officer. The purchase price of the real estate property was $0.4 million as determined by an independent third party broker's opinion of value. The transaction closed on January 11, 2017. Leased Real Estate Headquarters Lease The Company has entered into operating leases for its corporate headquarters and a storage space facility with an entity that is wholly owned by the Company’s chief executive officer. The Company has evaluated its relationship with the related party and concluded that the related party is not a variable interest entity because the Company has no direct ownership interest or relationship other than the leases. The lease for headquarters is for an initial term of twelve years through November 2022 with a renewal option for one 10-year term at prevailing market rates. The lease for storage space was through June 2016 and was leased on a month to month basis, thereafter. The Company pays rent, taxes, insurance, and maintenance expenses that arise from the use of the properties. Annual base rent for the corporate headquarters is $2.2 million and allows for adjustments to the rental rate annually for increases in the consumer price index. Lease expense recognized for the years ended December 31, 2018, 2017 and 2016 was $2.2 million, $2.1 million and $2.1 million, respectively. The lease expense was allocated between Direct service costs, excluding depreciation and amortization, and Selling, general and administrative in the consolidated statements of operations. In 2018, Medpace, Inc. entered into a multi-year lease agreement governing future occupancy of additional office space in Cincinnati, Ohio. The lease expires in 2040 and the Company has two 10-year options to extend the term of the lease. Deemed Assets and Deemed Landlord Liabilities The Company entered into two multi-year lease agreements governing the occupancy of space of two buildings in Cincinnati, Ohio with an entity that is wholly owned by the Company’s chief executive officer and certain members of his immediate family. In accordance with the accounting guidance related to leases, the Company was deemed in substance to be the owner of the property during the construction phase and at completion. Accordingly, the Company reflected the buildings and related liabilities as deemed assets from landlord building construction in Property and equipment, net, Other current liabilities, and Deemed landlord liabilities, respectively, on the consolidated balance sheets. The Company assumed occupancy in 2012 and the leases expire in 2027 with the Company having one 10-year option to extend the lease term. The deemed assets are being fully depreciated, on a straight line basis, over the 15-year term of the lease. Deemed landlord liabilities are recorded at their net present value when the Company enters into qualifying leases and are reduced as the Company makes periodic lease payments on the properties. Accretion expense is being recorded over the term of the lease as a component of Interest expense, net in the Company’s consolidated statements of operations. The Company paid $3.8 million, $3.8 million and $3.7 million during the years ended December 31, 2018, 2017 and 2016, respectively. The current and long-term portions of the Deemed landlord liability at December 31, 2018 were $2.1 million and $24.5 million, respectively. The current and long-term portions of the Deemed landlord liability at December 31, 2017 were $1.9 million and $26.6 million, respectively. The Company has recognized $14.6 million and $16.3 million, respectively, of deemed assets, net at December 31, 2018 and 2017 in the consolidated balance sheets. Travel Services Reynolds Jet Management (“Reynolds”) The Company incurs expenses for travel services for company executives provided by a private aviation charter company that is owned by the chief executive officer and the senior vice president of operations of the Company (“private aviation charter”). The Company may contract directly with the private aviation charter for the use of its aircraft or indirectly through a third party aircraft management and jet charter company (the “Aircraft Management Company”). The travel services provided are primarily for business purposes, with certain personal travel paid for as part of the executives’ compensation arrangements. The Aircraft Management Company also makes the private aviation charter aircraft available to third parties. The Company incurred travel expenses of $1.3 million, $1.1 million and $1.0 million during the years ended December 31, 2018, 2017 and 2016, respectively. These travel expenses are recorded in Selling, general and administrative in the Company’s consolidated statements of operations. As of December 31, 2018 and 2017, the Company had Accounts payable due to Reynolds of $0.2 million in the consolidated balance sheets, respectively.

Cash Flow Statement - Supplemen

Cash Flow Statement - Supplemental Information	12 Months Ended
	Dec. 31, 2018
Supplemental Cash Flow Information [Abstract]
Cash Flow Statement - Supplemental Information	15. CASH FLOW STATEMENT – SUPPLEMENTAL INFORMATION During the year ended December 31, 2017, the Company engaged in the following significant non-cash investing and financing activities: • Acquired net assets totaling $0.7 million consisting of net Deferred tax assets of $21.1 million, offset by net Deferred tax liabilities of $0.1 million and Deferred credits of $20.3 million in exchange for Accounts receivable and unbilled, net of $0.6 million and Other assets of $0.1 million.

Entity Wide Disclosures

Entity Wide Disclosures	12 Months Ended
	Dec. 31, 2018
Entity Wide Disclosures [Abstract]
Entity Wide Disclosures	16. ENTITY WIDE DISCLOSURES Operations By Geographic Location The Company conducts operations in North America, Europe, Africa, Asia-Pacific and Latin America through wholly-owned subsidiaries and representative sales offices. The Company attributes revenue to geographical locations based upon the location of the contracting entity. For the years ended December 31, 2018 and 2017, total revenue and service revenue attributable to the U.S. represented approximately 97% and 98%, respectively, of total consolidated total revenue and service revenue, net. The following table summarizes property and equipment, net by geographic region and is further broken down to show countries which account for 10% or more of total as of December 31, if any (in thousands): 2018 2017 Property and equipment, net: United States $ 38,609 $ 37,535 Europe Belgium 6,014 4,132 Other 5,500 5,134 Total Europe 11,514 9,266 Other 2,132 1,938 Total property and equipment, net $ 52,255 $ 48,739 Revenue by Category The following table disaggregates the Company’s revenue by major source (in thousands): Year Ended December 31, 2018 Therapeutic Area Oncology $ 189,026 Other 161,194 Metabolic 94,128 Cardiology 91,824 AVAI 76,739 Central Nervous System 53,904 Endocrine 26,002 Medical Devices 11,772 Total revenue $ 704,589

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	17. QUARTERLY FINANCIAL DATA (unaudited) The following table summarizes the Company's unaudited quarterly results of operations (in thousands, except per share data): 2018 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenue $ 163,077 $ 170,144 $ 179,253 $ 192,115 Total direct costs 117,254 116,676 123,996 131,133 Income from operations 20,119 23,345 26,918 30,666 Net income 14,551 16,568 19,305 22,761 Net income per share attributable to common shareholders - Basic $ 0.41 $ 0.46 $ 0.54 $ 0.64 Net income per share attributable to common shareholders - Diluted $ 0.40 $ 0.45 $ 0.52 $ 0.61 2017 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenue $ 106,611 $ 106,216 $ 110,643 $ 112,682 Total direct costs 63,935 63,619 65,106 68,803 Income from operations 15,944 16,279 17,198 15,437 Net income 8,447 9,553 9,831 11,291 Net income per share attributable to common shareholders - Basic $ 0.21 $ 0.24 $ 0.25 $ 0.30 Net income per share attributable to common shareholders - Diluted $ 0.20 $ 0.23 $ 0.25 $ 0.30

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Share Repurchases	Share Repurchases In November 2017, approved an agreement to repurchase 2,000,000 shares of the Company’s common stock from Cinven in connection with the Secondary Offering (as described below) for aggregate consideration of approximately $60.3 million, representing a purchase price of $30.16 per share. In August 2017, the Disinterested Directors of the Company approved a stock repurchase agreement with Medpace Limited Partnership, a Guernsey limited partnership (the “Limited Partnership” acting through its general partner, Medpace GP Limited, a Guernsey company, the “General Partner” and, the Limited Partnership acting through the General Partner, “Cinven”), pursuant to which the Company repurchased 2,000,000 shares of the Company’s common stock from Cinven for aggregate consideration of approximately $60.5 million, representing a purchase price of $30.27 per share. The Company funded the repurchase with cash on hand and $40.0 million in borrowings under our Senior Secured Revolving Credit Facility. In April 2017, the Board of the Company authorized a share repurchase program with an authorized repurchase level of $50.0 million. The share repurchase program was cancelled in the fourth quarter of 2017. Repurchases under the repurchase program took place in the open market or negotiated transactions, at the discretion of the Company’s management. During the year ended December 31, 2017, the Company repurchased 1,342,786 shares of its outstanding common stock for $34.7 million under this share repurchase program. The Company has elected to constructively retire all repurchased shares with all amounts paid in excess of Common stock par value reflected within Accumulated deficit in the Company’s consolidated balance sheets, except for 200,000 shares, which are reflected within treasury stock in the Company’s consolidated balance sheets.
Initial Public Offering	Initial Public Offering On August 11, 2016, the Company's common stock began trading on the NASDAQ Global Select Market (“NASDAQ”) under the symbol "MEDP". On August 16, 2016, the Company completed its initial public offering (“IPO”) of its common stock at a price to the public of $23.00 per share. The Company issued and sold 8,050,000 shares of common stock in the IPO, including 1,050,000 common shares issued pursuant to the full exercise of the underwriters' option to purchase additional shares. The IPO raised net proceeds of approximately $173.6 million after deducting underwriting discounts and commissions. As contemplated in the Company’s prospectus filed pursuant to Rule 424(b) under the Securities Act of 1933, as amended (the “Securities Act”), with the Securities and Exchange Commission on August 11, 2016, the net proceeds from the IPO, along with cash on hand, were used to repay $175.0 million of outstanding borrowings under the 2014 Senior Secured Term Loan Facility (as defined below) and $2.7 million of offering expenses.
Secondary Offerings	Secondary Offerings During the year ended December 31, 2018, Cinven sold a total of 16,399,997 shares of the Company’s common stock as part of multiple secondary offerings. The Company incurred professional fees in connection with the secondary offerings of $0.7 million during the year ended December 31, 2018. The fees are included within operating expenses in the accompanying consolidated statement of operations. As of August 27, 2018, Cinven does not beneficially own any shares of the Company’s outstanding common stock. The Company did not sell any shares in or receive any proceeds from the secondary offerings. During the year ended December 31, 2017, Cinven sold a total of 4,600,000 shares of the Company’s common stock as part of a secondary offering. The Company incurred professional fees in connection with the secondary offering of $0.4 million during year ended December 31, 2017. The fees are included within operating expenses in the accompanying consolidated statement of operations.
Principles of Consolidation and Presentation	Principles of Consolidation and Presentation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“US GAAP”) and include the accounts and operations of the Company and its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from these estimates. Significant items that are subject to management estimates and assumptions include revenue, net, allowances for doubtful accounts, acquisition purchase price allocations, long-lived asset impairment and useful lives, exit liabilities, stock-based compensation, uncertain income tax positions and contingencies.
Reportable Segments	Reportable Segments The Company emphasizes its full service outsourcing model, providing services focused on the development, management and execution of clinical trials. As part of this full service approach, the Company utilizes centralized systems, customer interface technology, support functions and processes that cross service offerings and align resources to deliver efficient clinical trial services. Given the full service approach, the chief executive officer, who is the chief operating decision maker (“CODM”) assesses the allocation of resources based on key metrics including revenue, backlog, and net awards by service offering and consolidated profitability and consolidated cash flows. Based on the Company’s full service model, internal management and reporting structure, and key metrics used by the CODM to make resource allocation decisions, management has determined that the Company’s operations consist of a single operating segment. Therefore, results of operations are presented as a single reportable segment.
Foreign Currencies	Foreign Currencies Assets and liabilities recorded in foreign currencies on foreign subsidiary financial statements are translated at the exchange rate on the balance sheet date, while equity accounts are translated at historical exchange rates. Revenue and expenses are recorded at average rates of exchange during the year. Translation adjustments are recorded to Accumulated other comprehensive loss in the consolidated statements of shareholders’ equity and consolidated statements of comprehensive income. Separately, net realized gains and losses on foreign currency transactions are included in Miscellaneous income (expense), net, on the consolidated statements of operations. Foreign currency transactions resulted in a net gain of $0.4 million during the year ended December 31, 2018 and net losses of $1.0 million and $0.7 million
Revenue Recognition	Revenue Recognition The Company generally enters into contracts with customers to provide services ranging in duration from a few months to several years. The contract terms generally provide for payments based on a fixed fee or unit-of-service arrangement. The Company accounts for revenue in accordance with ASC 606, Revenue from Contracts with Customers, which the Company adopted on January 1, 2018 using the modified retrospective implementation method. Revenue on contracts is recognized when or as the Company satisfies the contract performance obligations, at the amount that reflects the Company’s cumulative progress toward delivery of the performance obligation. This progress assessment is applied to the amount of consideration to which the Company expects to be paid for delivery of the performance obligation. The Company’s performance obligations are generally satisfied over time and related revenue is recognized as services are provided to meet these obligations. Contract Assumptions An arrangement is accounted for as a contract within the scope of ASC 606 when the Company and its customers approve the contract, are committed to perform their respective obligations, each party can identify its rights regarding the goods or services to be transferred, commercial substance is present, and it is probable that the Company will collect substantially all of the consideration to which it will be entitled in exchange for the goods or services that will be transferred to the customer. For the Company’s services to meet this criteria, contracts generally need to be written, pending regulatory hurdles required to commence work must be cleared, the study protocol must be completed, the customer must have adequate funding or reasonable path to funding to execute the contracted portion of the study, and the study must be actively moving forward. Once these criteria have been met, it is deemed that the Company and its customers are committed to perform their respective obligations. Depending on the timing of when these criteria are met, revenue recognition may vary significantly on a period over period basis. Accounting for contracts performed over a period of time involves the use of various assumptions to estimate tota l contract revenue and costs. The Company estimate s expected costs to complete a contract and recognize s contracted revenue over the life of the contract as those costs are incurred. Cost estimates are based on a detailed project budget and are developed based on many variables, including, but not limited to, the scope of the work, the complexity of the study, the participating geographic locations and the Company’s historical experience. To assist with the estimation of costs expected at completion over the life of a project, regular contract reviews are performed in which performance to date is compared to the most current estimate to complete assumptions. The reviews include an assessment of costs incurred to date compared to expectations based on budget assumptions and other circumstances specific to the project. The total estimated costs necessary to complete is updated and any revisions to the existing cost estimate results in cumulative adjustments to the amount of revenue recognized in the period in which the revisions are identified. In the case of cost estimates related to activities legally contracted as reimbursable in nature, including but not limited to investigator fee activity, these estimates also influence the Company’s assumed contract value and assumed remaining performance obligations. Because of the uncertainties inherent in estimating the costs necessary to fulfill contractual obligations, it is possible that estimates may change in the near term, resulting in a material change in revenue reported. Contracts generally provide for pricing modifications upon scope of work changes. The Company recognizes revenue, at an amount to which it expects to be entitled, related to work performed in connection with scope changes when the underlying services are performed and a binding contractual commitment has been established with the customer. If the Company’s customers do not agree to contract changes upon changes in the Company’s scope of work, the Company could be exposed to cost overruns and reduced contract profitability. Costs are not deferred in anticipation of contracts being awarded or amendments being finalized, but are expensed as incurred. Most contracts are terminable by the customer, either immediately or according to advance notice terms specified within the contracts. These contracts require payment of fees for services rendered through the date of termination and may require payment for subsequent services necessary to conclude the study or close out the contract. Final settlement amounts are agreed to with the customer based on remaining work to be performed. These amounts are included in revenue when the Company believes the amount can be estimated reliably and its realization is probable. In evaluating the probability of recognition, the Company considers the contractual basis for the settlement amount and the objective evidence available to support the amount. Certain contracts contain volume rebate arrangements with our customers that provide for rebates if certain specified spending thresholds are met. These obligations are considered as a reduction in revenue when it appears probable that the arrangement thresholds will be met, which can be at contract inception. Total revenue is presented net of rebates of $1.2 million, $0.2 million and less than $0.1 million in the consolidated statements of operations during the years ended December 31, 2018, 2017 and 2016, respectively. The Company occasionally enters into incentive fee arrangements with customers that provide for additional compensation if certain defined contractual milestones or performance thresholds are met. These additional fees are included in the estimated transaction price when there is a basis to reasonably estimate the amount of the fee and when achievement of the incentive milestone is deemed probable. These estimates are based on anticipated performance, the Company’s best judgment at the time or ultimately, upon achievement of the threshold or milestone. The Company records revenue net of any tax assessments by governmental authorities that are imposed and concurrent with specific revenue generating transactions. Performance Obligations Substantially all of the Company’s contracts consist of a single performance obligation, as the promise to transfer the individual services described in the contracts are not separately identifiable from other promises in the contracts, and therefore not distinct. Revenue recognition is determined by assessing the progress of performance completed or delivered to date compared to total services to be delivered under the terms of the arrangement. The measures utilized to assess progress on the satisfaction of performance are specific to the performance obligation identified in the contract. For the majority of the Company’s contract performance obligations, it utilizes the input method of cost to cost to measure progress, as the Company has determined that it is the most consistent measure of progress among contract tasks and represents the most faithful depiction of the transfer of services over the contract life. Under this method, the Company determines cost incurred to date for the services it provides compared to the total estimated costs at completion. For certain other contractual performance obligations, the Company has determined that an output method is the best measure of progress. These relate to certain unitized contracts, and the Company recognizes revenue in the period in which the unit is delivered compared to total contracted units. On December 31, 2018, the Company had approximately $1,060.7 million of performance obligations remaining to be performed for active projects.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that subject the Company to credit risk primarily consist of cash and cash equivalents and accounts receivable. The cash and cash equivalent balances are held and maintained with financial institutions with reputable credit ratings and, consequently, the Company believes that such funds are subject to minimal credit risk. The Company generally does not require collateral or other securities to support customer receivables. In the years ended December 31, 2018, 2017 and 2016, credit losses have been immaterial and within management’s expectations. At December 31, 2018 and 2017, there were no customers accounting for more than 10% of the Company’s accounts receivable.
Costs and Expenses	Costs and Expenses The Company incurs costs associated with service delivery including direct labor and related employee benefits, laboratory supplies, and other expenses. These costs are recorded in Direct service costs, excluding depreciation and amortization as a component of Total direct costs in the accompanying consolidated statements of operations. In addition, the Company incurs expenses on behalf of its customers for various project expenditures including, but not limited to, investigator site payments, travel, meetings, printing, and shipping and handling fees that are reimbursed by its customers at cost. These costs are included in Reimbursable out-of-pocket expenses as a component of Total direct costs in the accompanying consolidated statements of operations. Total direct costs are expensed as incurred and are not deferred in anticipation of contracts being awarded or finalization of changes in scope. Selling, general and administrative includes administrative payroll and related employee benefits, sales and marketing expenses, administrative travel, and other expenses not directly related to service delivery. Rent, utilities, supplies, and software license expenses are allocated between Total direct costs, and Selling, general and administrative based on the estimated contribution among service delivery and support function efforts on a percentage basis. Depreciation and amortization is reported separately in the accompanying consolidated statements of operations. Costs of sales and marketing activities not subject to recovery pursuant to customer contracts, such as feasibility assessments and negotiation of contracts, are expensed as incurred and recorded as a component of Selling, general and administrative in the accompanying consolidated statements of operations. Advertising expenses are recorded as a component of Selling, general and administrative expenses in the accompanying consolidated statements of operations. Total advertising expenses of $0.8 million, $0.6 million and $0.6 million Prior to the adoption of Accounting Standard Update No. 2014-09 ‘‘Revenue from Contracts with Customers”, fees paid to investigators and other disbursements in which the Company acts as an agent on behalf of the customer were recorded net in the consolidated statements of operations with no impact on the Company’s revenue or expenses. Funds received in advance of study expenditures were recorded as Pre-funded study cost liabilities on the consolidated balance sheets. Any pre-funded amounts remaining at the conclusion of a study were returned to the client. Pre-funded study cost disbursements of $138.7 and $150.3 million
Income Taxes	Income Taxes The Company’s consolidated U.S. federal income tax return is comprised of its U.S. subsidiaries and one of its foreign subsidiaries located in Korea. All foreign subsidiaries of the Company file tax returns in their local jurisdictions. The Company provides for income taxes on all transactions that have been recognized in the consolidated financial statements in accordance with accounting guidance governing income tax accounting. Accordingly, the impact of changes in income tax laws on deferred tax assets and deferred tax liabilities are recognized in net earnings in the period during which such changes are enacted. The Company records deferred tax assets and liabilities based on temporary differences between the financial statement bases and tax bases of assets and liabilities. Deferred tax assets are recorded for tax benefit carryforwards using tax rates anticipated to be in effect in the year in which the temporary differences are expected to reverse. If it does not appear more likely than not that the full value of a deferred tax asset will be realized, the Company records a valuation allowance against the deferred tax asset, with an offsetting charge to the Company’s income tax provision or benefit. The value of the Company’s deferred tax assets is estimated based on, among other things, the Company’s ability to generate a sufficient level of future taxable income. In estimating future taxable income, the Company has considered both positive and negative evidence, such as historical and forecasted results of operations, and has considered the implementation of prudent and feasible tax planning strategies. The Company’s current accounting position is that unremitted foreign earnings are indefinitely reinvested. Therefore, the Company has not recorded deferred foreign withholding taxes on the unremitted foreign earnings. Refer to Note 12 for further information regarding this assertion. The Company follows accounting guidance related to accounting for uncertainty in income taxes which requires significant judgment in determining what constitutes an individual tax position as well as assessing the possible outcome of each tax position. Changes in judgments as to recognition or measurement of tax positions can materially affect the estimate of the effective tax rate, and, consequently, the Company’s consolidated financial results. The Company considers many factors when evaluating and estimating tax positions and tax benefits, which may require periodic adjustments and which may not accurately anticipate actual outcomes. In addition, the calculation of tax liabilities involves dealing with uncertainties in the application of complex tax regulations in a multitude of jurisdictions. The Company determines its liability for uncertain tax positions globally. If the payment of these amounts ultimately proves to be unnecessary, the reversal of liabilities would result in tax benefits being recognized in the period when it is determined the liabilities are no longer necessary. If the calculation of the liability related to uncertain tax positions proves to be more or less than the ultimate assessment, a tax expense or tax benefit would result. Interest and penalties associated with uncertain tax positions are recognized as components of the Company’s Income tax provision.
Research and Development Credits	Research and Development Credits Research and development credits are available to the Company under tax laws in certain jurisdictions, based on qualifying research and development spend as defined under those tax laws. Certain tax jurisdictions provide refundable credits that are not wholly dependent on the Company’s income tax status or income tax position. In these circumstances the benefit of the credits is recorded as a reduction of operating expense. When they are wholly dependent upon the Company’s income tax position, research and development credits are recognized as a reduction of income tax expense.
Stock-Based Compensation	Stock-Based Compensation The Company has stock-based employee compensation plans for which it incurs compensation expense. Equity Awards In connection with the Company's IPO, the Board approved the formation of the 2016 Incentive Award Plan (the “2016 Plan”), which replaced our 2014 Equity Incentive Plan (the “2014 Plan”). The 2016 Plan provides for long-term equity incentive compensation for key employees, officers and non-employee directors. A variety of discretionary awards (collectively, the “Awards”) for employees and non-employee directors are authorized under the 2016 Plan, including vested common shares, stock options, stock appreciation rights (“SARs”), restricted stock awards (“RSAs”), restricted stock units (“RSUs”), or other cash based or stock dividend equivalent awards. The vesting of such awards may be conditioned upon either a specified period of time or the attainment of specific performance goals as determined by the administrator of the 2016 Plan. The option price and term are also subject to determination by the administrator with respect to each grant. Option prices are generally expected to be set at the market price of our common stock at the date of grant and option terms are not expected to exceed ten years. All outstanding Awards under the 2016 Plan are equity classified awards. The Company created the 2014 Plan, providing for the future issuance of vested shares, stock options, RSAs and RSUs in Medpace Holdings, Inc.’s common stock (the “2014 Plan Awards”). The 2014 Plan Awards were subject to either equity or liability-classification pursuant to the terms of the participant’s award agreement and the 2014 Plan based on accounting guidance which governs such transactions. Stock-based compensation expense for both the 2016 Plan and 2014 Plan is calculated using the fair value method on the grant date. The Company expenses stock-based compensation using a graded vesting schedule. For liability-classified awards under the 2014 Plan, the Company recorded fair value adjustments up to and including the settlement date. Changes in the fair value of the stock compensation liability that occurred during the requisite service period were recognized as compensation cost over the vesting period. Changes in the fair value of the stock compensation liability that occurred after the end of the requisite service period but before settlement, were compensation cost of the period in which the change occurred. As a result of the Company’s IPO, a condition of all outstanding stock options issued before August 10, 2016 under the 2014 Plan that previously required the exchange of the shares issued for incentive units in the equity of a non-consolidated related party was dissolved. All future exercises of options issued pursuant to the 2014 Plan will settle in unregistered shares of the Company. As a result of the modification in the settlement condition, the options are equity-classified instruments and changes in the fair value of the stock compensation liability that occur during the requisite service period are no longer recognized. Stock-based compensation expense is allocated between Total direct costs, and Selling, general and administrative in the consolidated statements of operations based on the underlying classification and scope of work for the employees receiving the Awards.
Net Income Per Share	Net Income Per Share Basic and diluted earnings or loss per share (“EPS”) are computed using the two-class method, which is an earnings allocation that determines EPS for each class of common stock and participating securities according to dividends declared and participation rights in undistributed earnings. The Company’s RSAs are considered participating securities because they are legally issued at the date of grant and holders are entitled to receive non-forfeitable dividends during the vesting term. The computation of diluted EPS includes additional common shares, such as unvested RSUs and stock options with exercise prices less than the average market price of the Company’s common stock during the period (“in-the-money options”), which would be considered outstanding under the treasury stock method. The treasury stock method assumes that additional shares would have to be issued in cases where the exercise price of stock options is less than the value of the common stock being acquired because the cash proceeds received from the stock option holder would not be sufficient to acquire that same number of shares. The Company does not compute diluted EPS in cases where the inclusion of such additional shares would be anti-dilutive in effect. The following table sets forth the computation of basic and diluted earnings per share for the years ended December 31, 2018, 2017 and 2016 (in thousands, except for earnings per share): Year Ended December 31, 2018 2017 2016 Weighted-average shares: Common shares outstanding 35,547 39,056 35,690 RSAs 142 90 88 Total weighted-average shares 35,689 39,146 35,778 Earnings per common share—Basic Net income $ 73,185 $ 39,122 $ 13,425 Less: Undistributed earnings allocated to RSAs 291 90 33 Net income available to common shareholders—Basic $ 72,894 $ 39,032 $ 13,392 Net income per common share—Basic $ 2.05 $ 1.00 $ 0.38 Basic weighted-average common shares outstanding 35,547 39,056 35,690 Effect of diluted shares 1,365 783 639 Diluted weighted-average shares outstanding 36,912 39,839 36,329 Net income per common share—Diluted $ 1.97 $ 0.98 $ 0.37 For the years ended December 31, 2018, 2017 and 2016, the computation of diluted EPS excludes the effect of (in thousands) 121, 63 and 0 stock options, respectively, due to each respective period’s average fair value of the Company’s common stock not exceeding the exercise prices.
Fair Value Measurements	Fair Value Measurements The Company follows accounting guidance related to fair value measurements that defines fair value, establishes a framework for measuring fair value, and establishes a hierarchy for inputs used in measuring fair value. This hierarchy maximizes the use of “observable” inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. The hierarchy specifies three levels based on the inputs, as follows: Level 1: Valuations based on quoted prices in active markets for identical assets or liabilities. Level 2: Valuations based on directly observable inputs or unobservable inputs corroborated by market data. Level 3: Valuations based on unobservable inputs supported by little or no market activity representing management’s determination of assumptions of how market participants would price the assets or liabilities. The fair value of financial instruments such as cash and cash equivalents, accounts receivable and unbilled, net, accounts payable, accrued expenses, and advanced billings approximate their carrying amounts due to their short term maturities. The Company does not have any recurring fair value measurements as of December 31, 2018. There were no transfers between Level 1, Level 2, or Level 3 during the years ended December 31, 2018, 2017 and 2016.
Cash and Cash Equivalents, including Restricted Cash	Cash and Cash Equivalents, including Restricted Cash Cash and cash equivalents, including restricted cash, are invested in demand deposits, all of which have an original maturity of three months or less. Restricted cash consists of customer funds received in advance and subject to specific restrictions, as well as amounts placed in escrow for contingent payments resulting from acquisitions or other contractual arrangements.
Accounts Receivable and Unbilled, Net	Accounts Receivable and Unbilled, Net Accounts receivable represent amounts due from the Company’s customers who are concentrated primarily in the pharmaceutical, biotechnology, and medical device industries. Unbilled services represent revenue recognized to date that is currently not billable to the customer pursuant to contractual terms. In general, amounts become billable upon the achievement of negotiated contractual events or in accordance with predetermined payment schedules. Amounts classified to unbilled services are those billable to customers within one year from the respective balance sheet date. The Company grants credit terms to its customers prior to signing a service contract and monitors the creditworthiness of its customers on an ongoing basis. The Company maintains an allowance for doubtful accounts based on specific identification of accounts receivable that are at risk of not being collected. Uncollectible accounts receivable are written off only after all reasonable collection efforts have been exhausted. Moreover, in some cases the Company requires advance payment from its customers for a portion of the study contract price upon the signing of a service contract. These advance payments are deferred and recognized as revenue as services are performed.
Inventory	Inventory Inventory, which consists primarily of laboratory supplies, is valued at the lower of cost or market. Inventory is stated at purchased cost using the first-in, first out (FIFO) cost method. The inventory balance is included in Prepaid expenses and other current assets in the consolidated balance sheets.
Property and Equipment	Property and Equipment Property and equipment is recorded at cost. Depreciation is provided on the straight-line method at rates adequate to allocate the cost of the applicable assets over their estimated useful lives, which is three to five years for computer hardware, software, phone, and medical imaging equipment, five to seven years for furniture and fixtures and other equipment, and thirty to forty years for buildings. The Company capitalizes costs of computer software developed for internal use and amortizes these costs on a straight-line basis over the estimated useful life, not to exceed three years. Leasehold improvements and deemed assets from landlord building construction are capitalized and amortized on a straight-line basis over the shorter of the estimated useful life of the improvement or the associated remaining lease term. Repairs and maintenance are expensed as incurred.
Leases	Leases The Company leases facilities and equipment to be used in its operations, some of which require capitalization in accordance with US GAAP. Upon the execution of new leases, the Company determines the appropriate classification of the lease as operating or capital and reflects the impact of this classification in its consolidated financial statements.
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill Goodwill represents the excess of purchase price over the fair value of net assets acquired in business combinations. The carrying value of goodwill is reviewed at least annually for impairment, or as indicators of potential impairment are identified, at the reporting unit level. The reporting units are Phase II-IV clinical research services, Laboratories, and Clinics as of December 31, 2018. The Company performs its annual impairment tests during the fourth quarter each year, utilizing the quantitative two step model defined by accounting guidance which governs such assessments. The first step involves the Company comparing each of its reporting unit carrying values, inclusive of assigned goodwill, to their respective estimated fair values. Fair value is estimated using a combination of the income approach, a discounted cash flow analysis, and the market approach, utilizing the guideline company method. If the calculation in the first step results in any of the reporting units’ carrying values exceeding their respective estimated fair values, a second step is performed. The second step requires the Company to allocate the fair value of the reporting unit derived in the first step to the fair value of the reporting unit’s net assets. Any fair value in excess of amounts allocated to such net assets represent the implied fair value of goodwill for that reporting unit. Any excess of reporting unit carrying value of goodwill over the implied fair value of goodwill results in an impairment. There was no indication of impairment related to goodwill based on the fourth quarter 2018 assessment. Intangible Assets The Company has an indefinite lived intangible asset related to its trade name. The carrying value of the trade name asset is reviewed at least annually for impairment, or as indicators of potential impairment are identified. The Company performs its annual impairment test in the fourth quarter each year in conjunction with its annual assessment of goodwill. The assessment consists of comparing the carrying value of the indefinite lived intangible asset to its estimated fair value, utilizing the relief from royalty method, an income approach valuation. There was no indication of impairment related to the trade name asset based on the fourth quarter 2018 assessment. Finite-lived intangible assets consist mainly of the value assigned to customer relationships, backlog and developed technologies. Finite-lived intangible assets are amortized straight-line or using an accelerated method over their estimated useful lives, which range in term from five to fifteen years.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets, primarily property and equipment and finite-lived intangible assets, are reviewed for impairment and the reasonableness of the estimated useful lives whenever events or changes in circumstances indicate that the carrying amounts of the assets may not be recoverable or that a change in useful life may be appropriate. Recoverability for long-lived assets is determined by comparing the forecasted undiscounted cash flows of the operation to which the assets relate to the carrying amount of the assets. If the undiscounted cash flows are less than the carrying amount of the assets, then the Company reduces the carrying value of the assets to estimated fair values, which are primarily based upon forecasted discounted cash flows. Fair value of long-lived assets is determined based on a combination of discounted cash flows and market multiples.
Advanced Billings	Advanced Billings Advanced billings represents cash received from customers, or billed amounts per an agreed upon payment schedule, in advance of services being performed or revenue being recognized.
Deemed Landlord Liabilities	Deemed Landlord Liabilities Deemed landlord liabilities are recorded at their net present value when the Company enters into qualifying leases and are reduced as the Company makes periodic lease payments on the properties.
Deferred Credit	Deferred Credit Deferred credit represents tax credits recognized initially in conjunction with the Nephrogenex asset acquisition that will be recognized within Income tax provision in proportion to the realization of the deferred tax assets and federal tax credits prospectively.
Other Current Liabilities and Other Long-Term Liabilities	Other Current Liabilities and Other Long-Term Liabilities Deferred rent represents the cumulative additional portion of rent expense recognized on a straight line basis in conjunction with the Company’s current leases at the balance sheet date. The Company defers incentives received from landlords for the purpose of making leasehold improvements. These liabilities are amortized as a component of rent expense over the term of the respective lease. Exit liabilities, if any exist, are recorded at their net present value to the extent the Company no longer receives any benefit from the related property and when the Company has ceased all use of the property. Asset retirement obligations, to the extent they exist, are recorded at their net present value and accreted to the Company’s estimate of liability at the time the obligation would be required to be satisfied.
Recently Adopted and Issued Accounting Standards	Recently Adopted Accounting Standards In January 2017, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2017-01, Business Combinations. The standard changes the definition of a business to assist entities with evaluating when a set of transferred assets and activities is a business. Under the new guidance, an entity first determines whether substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets. If this threshold is met, the set is not a business. If it’s not met, the entity then evaluates whether the set meets the requirement that a business include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create outputs. ASU 2017-01 is effective for fiscal years beginning after December 15, 2017, and for interim periods within those fiscal years. The Company, as permitted, early adopted ASU 2017-01 using the prospective method in the second quarter of 2017. ASU 2017-01 was considered in the asset acquisition described in Note 2. In March 2016, the FASB issued ASU No. 2016-09, Compensation - Stock Compensation: Improvements to Employee Share-Based Payment Accounting • Income taxes - Upon adoption of this standard, all excess tax benefits and tax deficiencies (including tax benefits of dividends, if distributed, on share-based payment awards) are recognized as income tax expense or benefit in the statement of operations. The tax effects of exercised or vested awards are treated as discrete items in the reporting period in which they occur. As a result, the Company recognized discrete adjustments to income tax expense for the year ended December 31, 2017 of less than $0.1 million related to excess tax benefits. The Company also recognizes excess tax benefits regardless of whether the benefit reduces taxes payable in the current period. The Company applied the prospective adoption approach for any unrecognized excess tax benefits beginning in 2017, which did not result in any cumulative-effect adjustment upon adoption. Prior periods have not been adjusted • Forfeitures - Prior to adoption, share-based compensation expense was recognized on a straight line basis, net of estimated forfeitures, such that expense was recognized only for share-based awards that were expected to vest. A forfeiture rate was estimated annually and revised, if necessary, in subsequent periods if actual forfeitures differed from initial estimates. Upon adoption, the Company no longer applies a forfeiture rate and instead accounts for forfeitures as they occur. The Company applied the modified retrospective adoption approach beginning in 2017 and booked an immaterial cumulative-effect adjustment to additional paid-in-capital and retained earnings within Shareholders’ Equity. Prior periods have not been adjusted. • Statements of Cash Flows - The Company historically accounted for excess tax benefits on the consolidated statements of cash flows as a financing activity. Upon adoption of this standard, excess tax benefits are classified along with other income tax cash flows as an operating activity. The Company elected to adopt this portion of the standard on a prospective basis beginning in 2017. Prior periods have not been adjusted. • Earnings Per Share - The Company uses the treasury stock method to compute diluted earnings per share, unless the effect would be anti-dilutive. Under this method, the Company is no longer required to estimate the tax rate and apply it to the dilutive share calculation for determining the dilutive earnings per share. The Company utilized the prospective adoption approach and applied this methodology beginning in 2017. Prior periods have not been adjusted. Upon adoption, no other aspects of ASU 2016-09 had an effect on the Company's consolidated financial statements or related footnote disclosures. In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-09 ‘‘Revenue from Contracts with Customers,’’ (“ASC 606”) to clarify the principles of recognizing revenue and create common revenue recognition guidance between US GAAP and International Financial Reporting Standards. The new standard became effective for the Company in the first quarter 2018. Under ASC 606, the majority of the Company’s contracts will have a single performance obligation that is satisfied over time, with revenue recognized based on overall project progress measured as of the financial statement date. This represents a change in the Company’s previous revenue accounting methodology, Accounting Standards Codification Topic 605, Revenue Recognition The Company elected to utilize the modified retrospective implementation method for its transition to ASC 606 as of January 1, 2018 (the “Implementation Date”). Under this implementation method, the Company recognized the cumulative effect of initially applying the ASC 606 revenue recognition guidance to contracts that were not completed at the Implementation Date. At the Implementation Date, the Company elected to reflect the aggregate effect of all contract modifications that occurred before January 1, 2018 in determining the satisfied and unsatisfied performance obligations and determination of the transaction price. The cumulative effect adjustment was recorded as a reduction to the opening balance of Accumulated deficit in the consolidated balance sheets in the amount of $5.7 million, with offsetting amounts of $23.9 million to Accounts receivable and unbilled, net, $(1.6) million to Deferred income taxes, $35.1 million to Accrued expenses, $(57.4) million to Pre-funded study costs and $38.9 million to Advanced billings, respectively. The amounts recorded to Accounts receivable and unbilled, net, Deferred income taxes, Accrued expenses, Pre-funded study costs, and Advanced billings reflect differences between revenue recognized and billings to customers by project as well as costs incurred but not settled as of the Implementation Date. The above disclosed cumulative effect adjustments have been revised from the amounts previously disclosed in the Company’s interim financial statements filed on Form 10-Q for the quarterly periods ended March 31, 2018, June 30, 2018 and September 30, 2018 to correct certain immaterial misstatements to the opening balance sheet adoption impact of the standard. The effects of these misstatements were immaterial to the Company’s results of operations. In connection with the implementation of ASC 606 on the modified retrospective method, the Company is presenting additional information to assist with the comparability of select line items of the current and prior period year to date reporting in its consolidated balance sheets and consolidated statements of operations. Below the Company has presented the amount by which each financial statement line item is affected in the current reporting period by the application of ASC 606 as compared with the guidance that was in effect before the change Year Ended December 31, 2018 As Reported Adjustments As Revised under ASC 605 Revenue: Revenue, net $ 704,589 $ (704,589 ) $ - Service revenue, net - 478,063 478,063 Reimbursed out-of-pocket revenue - 71,305 71,305 Total revenue 704,589 (155,221 ) 549,368 Operating expenses: Direct service costs, excluding depreciation and amortization 252,284 - 252,284 Reimbursed out-of-pocket expenses 236,775 (165,470 ) 71,305 Total direct costs 489,059 (165,470 ) 323,589 Total operating expenses 603,541 (165,470 ) 438,071 Income from operations 101,048 10,249 111,297 Income before income taxes 93,951 10,249 104,200 Income tax provision 20,766 1,882 22,648 Net income $ 73,185 $ 8,367 $ 81,552 Net income per share attributable to common shareholders: Basic $ 2.05 $ 0.24 $ 2.29 Diluted $ 1.97 $ 0.23 $ 2.20 Weighted average common shares outstanding: Basic 35,547 - 35,547 Diluted 36,912 - 36,912 ASSETS As of December 31, 2018 Current assets: As Reported Adjustments As Revised under ASC 605 Accounts receivable and unbilled, net 133,449 (28,729 ) 104,720 Prepaid expenses and other current assets 21,383 1,147 22,530 Total current assets 178,114 (27,582 ) 150,532 Deferred income taxes 713 (389 ) 324 Total assets $ 967,933 $ (27,971 ) $ 939,962 LIABILITIES AND SHAREHOLDERS’ EQUITY Current liabilities: Accrued expenses 87,493 (51,109 ) 36,384 Pre-funded study costs - 61,156 61,156 Advanced billings 147,935 (41,732 ) 106,203 Other current liabilities 4,861 (590 ) 4,271 Total current liabilities 257,026 (32,275 ) 224,751 Deferred income tax liability 439 2,049 2,488 Other long-term liabilities 12,804 (382 ) 12,422 Total liabilities 378,230 (30,608 ) 347,622 Shareholders’ equity: Accumulated deficit (41,487 ) 2,637 (38,850 ) Total shareholders’ equity 589,703 2,637 592,340 Total liabilities and shareholders’ equity $ 967,933 $ (27,971 ) $ 939,962 CASH FLOWS FROM OPERATING ACTIVITIES: Year Ended December 31, 2018 As Reported Adjustments As Revised under ASC 605 Net income 73,185 8,367 81,552 Adjustments to reconcile net income to net cash provided by operating activities: Deferred income tax provision 3,942 4,002 7,944 Changes in assets and liabilities: Accounts receivable and unbilled, net (27,047 ) 4,842 (22,205 ) Prepaid expenses and other current assets (1,241 ) (1,147 ) (2,388 ) Accrued expenses 29,029 (15,967 ) 13,062 Pre-funded study costs - 3,782 3,782 Advanced billings 35,593 (2,907 ) 32,686 Other assets and liabilities, net 1,925 (972 ) 953 Net cash provided by operating activities 156,584 - 156,584 Recently Issued Accounting Standards In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (“ASC 842”). The guidance in ASC 842 supersedes the lease recognition requirements in ASC Topic 840, Leases (FAS 13) (“ASC 840”). ASC 842 requires an entity to recognize assets and liabilities arising from a lease for both financing and operating leases, along with additional qualitative and quantitative disclosures. ASC 842 is effective for fiscal years beginning after December 15, 2018, with early adoption permitted. ASC 842 allows by policy election, an entity to choose its transition approach. Entities must adopt ASC 842 on a either a modified retrospective basis to each prior reporting period presented or through an optional alternative method referred to as the “Comparatives Under ASC 840 Approach” which allows entities to apply the new requirements to only those leases that exist as of January 1, 2019. The Company has elected to adopt ASC 842 utilizing the Comparatives Under ASC 840 Approach. Under this approach, the Company will not be required to recast comparative periods when transitioning to the new guidance. The Company will also not be required to present comparative period disclosures under the new guidance in the period of adoption and any cumulative catch up adjustment for differences between ASC 842 and ASC 840 will be recorded upon adoption. ASC 842 also allows for the election of certain practical expedients that are meant to ease the burden of transitioning to ASC 842 while still achieving compliance. The Company will elect the “package of three” practical expedient allowing the Company to carry forward decisions made and documented under current US GAAP, rather than reassessing all of the Company’s contracts to determine whether they are or contain leases and how they would be classified under ASC 842. The Company has decided not to elect the hindsight practical expedient, which if elected would require the Company to reassess the lease term and assessment of impairment for all of the Company’s leases using the facts and circumstances known up to the adoption date of the standard. The Company continues to evaluate the potential impact of adopting this standard on its business policies, processes and systems, internal control over financial reporting environment, and financial reporting disclosures. The most significant impact of adoption will be the conversion of the Company’s headquarter office buildings that are currently classified as deemed assets and liabilities to leases to be accounted for within the scope of ASC 842. This will result in a cumulative adjustment to retained earnings to account for the difference in the expense recognition at the time of adoption as well as a reclass of the Deemed Landlord Liability and deemed assets within Property and Equipment, net to right of use assets and right of use liabilities. Additionally, all existing operating leases will be recorded on the balance sheet as right-of-use (“ROU”) assets with related obligations for lease payments presented as other current liabilities, and ROU lease liabilities. To the extent we identify financing leases, these will be recorded on the balance sheet as property and equipment, with the related payment obligations recorded as other current liabilities, and other long-term liabilities. In February 2018, the FASB issued ASU 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. ASU 2018-02 allows for an entity to elect to reclassify the income tax effects on items within accumulated other comprehensive income resulting from U.S. tax reform to retained earnings. The guidance may be applied either in the period of adoption or retrospectively to each period (or periods) in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Cuts and Jobs Act is recognized and is effective for fiscal years beginning after December 15, 2018 with early adoption permitted, including interim periods within those years. The Company will adopt this guidance in the first quarter of 2019 and does not expect a material impact on its consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Schedule of Reconciliation of Denominators and Additional Shares that are Excluded from the Calculation of EPS	The following table sets forth the computation of basic and diluted earnings per share for the years ended December 31, 2018, 2017 and 2016 (in thousands, except for earnings per share): Year Ended December 31, 2018 2017 2016 Weighted-average shares: Common shares outstanding 35,547 39,056 35,690 RSAs 142 90 88 Total weighted-average shares 35,689 39,146 35,778 Earnings per common share—Basic Net income $ 73,185 $ 39,122 $ 13,425 Less: Undistributed earnings allocated to RSAs 291 90 33 Net income available to common shareholders—Basic $ 72,894 $ 39,032 $ 13,392 Net income per common share—Basic $ 2.05 $ 1.00 $ 0.38 Basic weighted-average common shares outstanding 35,547 39,056 35,690 Effect of diluted shares 1,365 783 639 Diluted weighted-average shares outstanding 36,912 39,839 36,329 Net income per common share—Diluted $ 1.97 $ 0.98 $ 0.37
Summary of Impact of Adoption of Accounting Standards	In connection with the implementation of ASC 606 on the modified retrospective method, the Company is presenting additional information to assist with the comparability of select line items of the current and prior period year to date reporting in its consolidated balance sheets and consolidated statements of operations. Below the Company has presented the amount by which each financial statement line item is affected in the current reporting period by the application of ASC 606 as compared with the guidance that was in effect before the change Year Ended December 31, 2018 As Reported Adjustments As Revised under ASC 605 Revenue: Revenue, net $ 704,589 $ (704,589 ) $ - Service revenue, net - 478,063 478,063 Reimbursed out-of-pocket revenue - 71,305 71,305 Total revenue 704,589 (155,221 ) 549,368 Operating expenses: Direct service costs, excluding depreciation and amortization 252,284 - 252,284 Reimbursed out-of-pocket expenses 236,775 (165,470 ) 71,305 Total direct costs 489,059 (165,470 ) 323,589 Total operating expenses 603,541 (165,470 ) 438,071 Income from operations 101,048 10,249 111,297 Income before income taxes 93,951 10,249 104,200 Income tax provision 20,766 1,882 22,648 Net income $ 73,185 $ 8,367 $ 81,552 Net income per share attributable to common shareholders: Basic $ 2.05 $ 0.24 $ 2.29 Diluted $ 1.97 $ 0.23 $ 2.20 Weighted average common shares outstanding: Basic 35,547 - 35,547 Diluted 36,912 - 36,912 ASSETS As of December 31, 2018 Current assets: As Reported Adjustments As Revised under ASC 605 Accounts receivable and unbilled, net 133,449 (28,729 ) 104,720 Prepaid expenses and other current assets 21,383 1,147 22,530 Total current assets 178,114 (27,582 ) 150,532 Deferred income taxes 713 (389 ) 324 Total assets $ 967,933 $ (27,971 ) $ 939,962 LIABILITIES AND SHAREHOLDERS’ EQUITY Current liabilities: Accrued expenses 87,493 (51,109 ) 36,384 Pre-funded study costs - 61,156 61,156 Advanced billings 147,935 (41,732 ) 106,203 Other current liabilities 4,861 (590 ) 4,271 Total current liabilities 257,026 (32,275 ) 224,751 Deferred income tax liability 439 2,049 2,488 Other long-term liabilities 12,804 (382 ) 12,422 Total liabilities 378,230 (30,608 ) 347,622 Shareholders’ equity: Accumulated deficit (41,487 ) 2,637 (38,850 ) Total shareholders’ equity 589,703 2,637 592,340 Total liabilities and shareholders’ equity $ 967,933 $ (27,971 ) $ 939,962 CASH FLOWS FROM OPERATING ACTIVITIES: Year Ended December 31, 2018 As Reported Adjustments As Revised under ASC 605 Net income 73,185 8,367 81,552 Adjustments to reconcile net income to net cash provided by operating activities: Deferred income tax provision 3,942 4,002 7,944 Changes in assets and liabilities: Accounts receivable and unbilled, net (27,047 ) 4,842 (22,205 ) Prepaid expenses and other current assets (1,241 ) (1,147 ) (2,388 ) Accrued expenses 29,029 (15,967 ) 13,062 Pre-funded study costs - 3,782 3,782 Advanced billings 35,593 (2,907 ) 32,686 Other assets and liabilities, net 1,925 (972 ) 953 Net cash provided by operating activities 156,584 - 156,584

Contract Assets and Contract _2

Contract Assets and Contract Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
Revenue From Contract With Customer [Abstract]
Summary of Company's Contract Asset and Contract Liability	Accounts receivable and unbilled, net consisted of the following (in thousands): As of December 31, January 1, December 31, 2018 2018 Adjustments 2017 Accounts receivable $ 85,120 $ 70,943 $ 15,344 $ 55,599 Unbilled receivables 49,361 36,696 8,543 28,153 Less: allowance for doubtful accounts (1,032 ) (673 ) - (673 ) Total accounts receivable and unbilled, net $ 133,449 $ 106,966 $ 23,887 $ 83,079 Advanced billings consisted of the following (in thousands): As of December 31, January 1, December 31, 2018 2018 Adjustments 2017 Advanced billings $ 147,935 $ 112,613 $ 38,857 $ 73,756 Pre-funded study costs $ - $ - $ (57,406 ) $ 57,406
Schedule of Allowance for Doubtful Account Activity	A rollforward of allowance for doubtful account activity is as follows: Year Ended December 31, 2018 2017 2016 Allowance for doubtful accounts - beginning balance $ (673 ) $ (3,222 ) $ (1,724 ) Current year provision (791 ) (250 ) (2,166 ) Write-offs, recoveries and the effects of foreign currency exchange 432 2,799 668 Allowance for doubtful accounts - ending balance $ (1,032 ) $ (673 ) $ (3,222 )

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Summary of Property and Equipment, Net	Property and equipment, net consisted of the following at December 31 (in thousands): 2018 2017 Land $ 1,240 $ 972 Equipment 15,437 12,171 Furniture, fixtures, and leasehold improvements 20,892 21,280 Computer hardware, software, and phone equipment 11,566 9,571 Buildings 8,145 2,559 Deemed assets from landlord building construction 22,752 22,752 Construction-in-progress 5,334 5,554 Property and equipment at cost 85,366 74,859 Less: Accumulated depreciation (33,111 ) (26,120 ) Property and equipment, net $ 52,255 $ 48,739

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets, Net	Intangible assets, net consisted of the following at December 31 (in thousands): 2018 2017 Intangible assets: Finite-lived intangible assets: Carrying amount: Backlog $ 72,630 $ 72,630 Customer relationships 145,051 145,051 Developed technologies 54,475 54,475 Other 3,074 3,074 Total finite-lived intangible assets 275,230 275,230 Accumulated amortization: Backlog (72,630 ) (72,630 ) Customer relationships (110,636 ) (92,661 ) Developed technologies (51,751 ) (40,856 ) Other (2,680 ) (1,989 ) Total accumulated amortization (237,697 ) (208,136 ) Total finite-lived intangible assets, net 37,533 67,094 Trade name (indefinite-lived) 31,646 31,646 Total intangible assets, net $ 69,179 $ 98,740
Schedule of Estimated Amortization Expense of Intangible Assets	As of December 31, 2018, estimated amortization expense of the Company’s intangible assets for each of the next five years and thereafter is as follows (in thousands): 2019 $ 14,829 2020 7,876 2021 5,114 2022 3,353 2023 2,199 Later years 4,162 $ 37,533

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Payables And Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following at December 31 (in thousands): 2018 2017 Employee compensation and benefits $ 31,344 $ 19,707 Project related reimbursable expenses 51,109 - Other 5,040 3,966 Total accrued expenses $ 87,493 $ 23,673

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Schedule of Debt	Debt consisted of the following at December 31 (in thousands): 2018 2017 Revolving credit facility $ - $ 70,000 Term loan 80,438 152,625 Less unamortized discount (282 ) (399 ) Less unamortized term loan debt issuance costs (435 ) (615 ) Less current portion of long-term debt - (16,500 ) Long-term debt, net, less current portion $ 79,721 $ 205,111
Schedule of Principal Payments on Debt Due	Principal payments on debt are due as follows (in thousands): 2019 - 2020 - 2021 80,438 Total $ 80,438

Commitments, Contingencies, a_2

Commitments, Contingencies, and Guarantees (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Schedule of Minimum Future Lease Payments	As of December 31, 2018, minimum future lease payments required under these leases are as follows (in thousands): Non-Related Total Related Party Parties Operating Operating Operating Leases Leases Leases 2019 $ 1,987 $ 6,186 $ 8,173 2020 6,843 6,617 13,460 2021 6,964 5,873 12,837 2022 6,757 3,694 10,451 2023 5,229 3,257 8,486 Thereafter 103,870 5,752 109,622 Total minimum lease payments $ 131,650 $ 31,379 $ 163,029
Schedule of Minimum Annual Payments Required in Conjunction with Landlord Liability	As of December 31, 2018, minimum annual payments required in conjunction with the Deemed landlord liabilities are as follows (in thousands): Related Party Total Minimum Lease Less: Principal Payments Interest Amounts Due 2019 $ 3,918 $ 1,818 $ 2,100 2020 3,988 1,662 2,326 2021 4,039 1,490 2,549 2022 4,092 1,301 2,791 2023 4,145 1,095 3,050 Thereafter 15,697 1,929 13,768 Total $ 35,879 $ 9,295 $ 26,584

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Schedule of Weighted-Average Assumptions Used in BSM Model to Calculate Fair Value of Options	The following table sets forth the key weighted-average assumptions used in the BSM Model to calculate the fair value of options: Year Ended December 31, 2018 2017 2016 Expected holding period - years 5.4 5.4 3.6 Expected volatility 27.0% 28.0% 30.2% Risk-free interest rate 2.8% 2.0% 1.0% Expected dividend yield 0.0% 0.0% 0.0%
Schedule of Grant Date Fair Value and Stock-based Compensation Expense Allocated	The following table summarizes the grant date fair values of stock options and restricted shares issued during the period as well as the allocation of stock-based compensation expense to Total direct costs, and Selling, general and administrative reported in the consolidated statements of operations: Year Ended December 31, 2018 2017 2016 Weighted average, grant date fair value Stock options $ 11.51 $ 8.54 $ 6.91 Restricted shares (RSAs and RSUs) $ 49.38 $ 31.90 $ 15.08 Stock-based compensation expense allocated to: Total direct costs $ 4,132 $ 2,128 $ 5,555 Selling, general, and administrative 2,367 2,335 4,260 Total stock-based compensation expense $ 6,499 $ 4,463 $ 9,815
Schedule of Stock Option Activity	The following table sets forth the Company’s stock option activity: Year Ended December 31, 2018 2017 2016 Weighted Weighted Weighted Average Options Exercise Price Options Exercise Price Shares Exercise Price Outstanding - beginning of Period 2,782,868 $ 20.73 2,350,166 $ 17.57 1,794,709 $ 15.42 Granted 584,301 $ 37.72 853,896 $ 28.67 683,001 $ 22.80 Exercised (169,771 ) $ 14.98 (116,787 ) $ 15.52 (36,980 ) $ 14.50 Forfeited/Expired (252,358 ) $ 23.69 (304,407 ) $ 20.55 (90,564 ) $ 15.85 Outstanding - end of period 2,945,040 $ 24.18 2,782,868 $ 20.73 2,350,166 $ 17.57 Exercisable - end of period 1,096,116 $ 16.01 917,592 $ 15.40 647,343 $ 15.22
Schedule of Restricted Share Activity	The following table sets forth the Company’s Restricted Share activity: Year Ended December 31, 2018 2017 2016 Shares/Units Shares/Units Shares/Units Outstanding and unvested - beginning of period 183,629 59,258 90,697 Granted 300,200 156,000 11,111 Vested (29,629 ) (29,629 ) (41,069 ) Forfeited (33,000 ) (2,000 ) (1,481 ) Outstanding and unvested - end of period 421,200 183,629 59,258 Cumulative vested shares - end of period 1,913,916 1,884,287 1,854,658
Schedule of Stock Options Expected To Vest, Stock Options Exercisable, and Unvested Restricted Share Awards Expected To Vest	The following table summarizes information about stock options expected to vest, stock options exercisable, and unvested restricted share awards expected to vest at December 31, 2018: Weighted Average Weighted Average Exercise Stock Restricted Remaining Price Options Shares Life (Years) December 31, 2018 Number of stock options expected to vest $ 24.18 2,945,040 - 4.4 Number of Restricted Shares expected to vest - 421,200 Total expected to vest - December 31, 2018 2,945,040 421,200 Total stock options exercisable - December 31, 2018 $ 16.01 1,096,116 3.0 Unrecognized compensation cost - December 31, 2018 (in thousands) $ 10,021 $ 15,734 Weighted average years over which unrecognized compensation cost will be recognized 2.7 3.5
Schedule of Aggregate Intrinsic Value of Stock Options Exercised, Fair Values of Awards Vested, and Share Based Liabilities Settled	The following table sets forth the aggregate intrinsic value of stock options exercised, the fair values of awards vested, and share based liabilities settled during the respective periods (in thousands): Year Ended December 31, 2018 2017 2016 Total intrinsic value of stock options exercised $ 5,326 $ 1,619 $ 403 Total grant-date fair value of stock options vested $ 1,417 $ 1,317 $ 1,384 Total grant-date fair value of restricted shares vested $ 447 $ 447 $ 614 Total settlement date fair value of restricted shares vested $ 1,568 $ 1,074 $ 1,236 Total share-based liabilities settled $ - $ - $ 76

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of Components of Income Before Income Taxes	The components of income before income taxes consisted of the following (in thousands): Year Ended December 31, 2018 2017 2016 Domestic $ 88,014 $ 52,986 $ 18,016 Foreign jurisdictions $ 5,937 $ 3,959 $ 3,941 Income before income taxes $ 93,951 $ 56,945 $ 21,957
Schedule of Income Tax Provision	Income tax provision consisted of the following (in thousands): Current Deferred Total Year ended December 31, 2018 U.S. Federal $ 13,372 $ 4,172 $ 17,544 U.S. state and local 1,912 (116 ) 1,796 Foreign jurisdictions 1,408 18 1,426 $ 16,692 $ 4,074 $ 20,766 Year ended December 31, 2017 U.S. Federal $ 10,953 $ 3,466 $ 14,419 U.S. state and local 2,032 51 2,083 Foreign jurisdictions 1,576 (255 ) 1,321 $ 14,561 $ 3,262 $ 17,823 Year ended December 31, 2016 U.S. Federal $ 15,105 $ (8,784 ) $ 6,321 U.S. state and local 1,636 (524 ) 1,112 Foreign jurisdictions 710 389 1,099 $ 17,451 $ (8,919 ) $ 8,532
Summary Of Difference Between Statutory Rate for Federal Income Tax and Effective Income Tax Rate	The difference between the statutory rate for federal income tax and the effective income tax rate was as follows (in thousands): Year Ended December 31, 2018 2017 2016 Income tax expense calculated at the federal statutory rate $ 19,730 21.0 % $ 19,931 35.0 % $ 7,685 35.0 % Effect of: State and local taxes, net of federal benefit 1,978 2.1 1,606 2.8 912 4.2 Tax on foreign earnings, net of tax credits and deductions 172 0.2 (69 ) (0.1 ) (26 ) (0.1 ) Tax reform adjustment (195 ) (0.2 ) (3,418 ) (6.0 ) - - Write off of Deferred Tax Assets 509 0.6 - - - - Deferred credit (802 ) (0.9 ) (1,053 ) (1.9 ) - - Change in valuation allowance - - - - - - Permanent items: Stock-based awards (651 ) (0.7 ) (179 ) (0.3 ) (534 ) (2.4 ) Tax reform adjustment 126 0.1 574 1.0 - - Other 687 0.7 483 0.9 174 0.8 State/Local tax credits (1,253 ) (1.3 ) (1,187 ) (2.1 ) (1,049 ) (4.8 ) Foreign tax credits (727 ) (0.8 ) - - - - Change in liability for uncertain tax positions 1,102 1.2 1,141 2.0 1,212 5.5 Other 90 0.1 (6 ) (0.0 ) 158 0.7 $ 20,766 22.1 % $ 17,823 31.3 % $ 8,532 38.9 %
Schedule of Components of Company's Net Deferred Tax Asset (Liability)	Components of the Company’s net deferred tax asset (liability) included in the consolidated balance sheets consisted of the following at December 31 (in thousands): 2018 2017 Deferred tax assets: Accrued liabilities $ 18,670 $ 17,563 Depreciation and amortization 872 980 Foreign operating loss carryforward 248 246 U.S. federal tax credits and carryforward - 8,152 U.S. state and local tax credits and carryforward 223 1,799 Other 41 667 Valuation allowance (169 ) (2,394 ) Total deferred tax assets 19,885 27,013 Deferred tax liabilities: Depreciation and amortization (18,803 ) (20,117 ) Prepaid expenses (550 ) (572 ) Other (258 ) (541 ) Total deferred tax liabilities (19,611 ) (21,230 ) Net deferred tax asset $ 274 $ 5,783
Schedule of Annual Activity Related to Valuation Allowance	Annual activity related to the Company’s valuation allowance is as follows (in thousands): Year Ended December 31, 2018 2017 2016 Beginning Balance $ 2,394 $ 987 $ 1,021 Additions charged to expense - - - Additions due to asset acquisition - 2,033 - Reductions from utilization, reassessments and expirations (2,225 ) 3 (34 ) Remeasurement due to effect of tax reform - (629 ) - Ending Balance $ 169 $ 2,394 $ 987
Schedule of Gross Unrecognized Tax Benefits	A reconciliation of the beginning and ending balances of the total amounts of gross unrecognized tax benefits is as follows (in thousands): Year Ended December 31, 2018 2017 2016 Beginning Balance $ 6,890 $ 5,698 $ 2,604 Increases in tax positions for prior years - 5 - Decreases in tax positions for prior years (579 ) - (196 ) Increases in tax positions for current year 2,214 1,187 3,365 Lapse in statute of limitations - - (75 ) Ending Balance $ 8,525 $ 6,890 $ 5,698

Miscellaneous Income (Expense_2

Miscellaneous Income (Expense), Net (Tables)	12 Months Ended
	Dec. 31, 2018
Other Income And Expenses [Abstract]
Components of Miscellaneous Income (Expense), Net	Miscellaneous income (expense), net consisted of the following (in thousands): Year Ended December 31, 2018 2017 2016 Net gain (loss) on foreign-currency transactions $ 386 $ (1,004 ) $ (660 ) Other income 674 650 237 Miscellaneous income (expense), net $ 1,060 $ (354 ) $ (423 )

Entity Wide Disclosures (Tables

Entity Wide Disclosures (Tables)	12 Months Ended
	Dec. 31, 2018
Entity Wide Disclosures [Abstract]
Summary of Property and Equipment, Net by Geographic Region	The following table summarizes property and equipment, net by geographic region and is further broken down to show countries which account for 10% or more of total as of December 31, if any (in thousands): 2018 2017 Property and equipment, net: United States $ 38,609 $ 37,535 Europe Belgium 6,014 4,132 Other 5,500 5,134 Total Europe 11,514 9,266 Other 2,132 1,938 Total property and equipment, net $ 52,255 $ 48,739
Summary of Revenue by Major Source	The following table disaggregates the Company’s revenue by major source (in thousands): Year Ended December 31, 2018 Therapeutic Area Oncology $ 189,026 Other 161,194 Metabolic 94,128 Cardiology 91,824 AVAI 76,739 Central Nervous System 53,904 Endocrine 26,002 Medical Devices 11,772 Total revenue $ 704,589

Quarterly Financial Data (Una_2

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Schedule of Unaudited Quarterly Results of Operations	The following table summarizes the Company's unaudited quarterly results of operations (in thousands, except per share data): 2018 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenue $ 163,077 $ 170,144 $ 179,253 $ 192,115 Total direct costs 117,254 116,676 123,996 131,133 Income from operations 20,119 23,345 26,918 30,666 Net income 14,551 16,568 19,305 22,761 Net income per share attributable to common shareholders - Basic $ 0.41 $ 0.46 $ 0.54 $ 0.64 Net income per share attributable to common shareholders - Diluted $ 0.40 $ 0.45 $ 0.52 $ 0.61 2017 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenue $ 106,611 $ 106,216 $ 110,643 $ 112,682 Total direct costs 63,935 63,619 65,106 68,803 Income from operations 15,944 16,279 17,198 15,437 Net income 8,447 9,553 9,831 11,291 Net income per share attributable to common shareholders - Basic $ 0.21 $ 0.24 $ 0.25 $ 0.30 Net income per share attributable to common shareholders - Diluted $ 0.20 $ 0.23 $ 0.25 $ 0.30

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Aug. 16, 2016	Nov. 30, 2017	Aug. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Apr. 30, 2017
Basis Of Presentation [Line Items]
Repurchases of common stock, value				$ 0	$ 155,583	$ 0
Treasury stock shares				200,000	200,000
Repayments of outstanding borrowings				$ 70,000	$ 30,000	0
Offering expenses				0	0	$ 2,719
2014 Senior Secured Term Loan Facility
Basis Of Presentation [Line Items]
Repayments of outstanding borrowings	$ 175,000
Share Repurchase Program
Basis Of Presentation [Line Items]
Repurchases of common stock, value					$ 34,700
Repurchases of outstanding common stock, shares					1,342,786
Maximum
Basis Of Presentation [Line Items]
Stock repurchase program, authorized amount							$ 50,000
Senior Secured Revolving Credit Facility
Basis Of Presentation [Line Items]
Share repurchases funding through borrowings			$ 40,000
Cinven
Basis Of Presentation [Line Items]
Repurchases of common stock, value			$ 60,500
Purchase price of repurchased shares			$ 30.27
Repurchases of outstanding common stock, shares			2,000,000
Secondary Offering | Operating Expenses
Basis Of Presentation [Line Items]
Professional fees				$ 700	$ 400
Secondary Offering | Senior Secured Revolving Credit Facility
Basis Of Presentation [Line Items]
Share repurchases funding through borrowings		$ 60,000
Secondary Offering | Cinven
Basis Of Presentation [Line Items]
Repurchases of outstanding common stock, shares		2,000,000
Repurchases of common stock, value		$ 60,300
Purchase price of repurchased shares		$ 30.16
Shares issued and sold				16,399,997	4,600,000
Initial Public Offering
Basis Of Presentation [Line Items]
Shares issued and sold, price per share	$ 23
Shares issued and sold	8,050,000
Net proceeds from issuance IPO	$ 173,600
Offering expenses	$ 2,700
Exercise of Underwriters' Option
Basis Of Presentation [Line Items]
Shares issued and sold	1,050,000

Acquisition - Additional Inform

Acquisition - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	May 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Noncash Or Part Noncash Acquisitions [Line Items]
Deferred tax assets			$ 21,100
Deferred tax liabilities			100
Deferred credit		$ 3,756	$ 11,468
Cinven
Noncash Or Part Noncash Acquisitions [Line Items]
Disposal of deferred tax assets		7,400
Reduction in deferred credit		$ 6,900
NephroGenex, Inc.
Noncash Or Part Noncash Acquisitions [Line Items]
Bankruptcy proceedings unsecured claim in exchange of common stock percentage	100.00%
Consideration paid	$ 1,200
Intangible assets	500
Deferred tax assets	22,200
Tax effected net operating losses	13,500
Tax effected capitalized research and development expenses	8,500
Tax effected federal tax credits	200
Deferred tax liabilities	100
Deferred credit	$ 21,400

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)Customershares	Dec. 31, 2017USD ($)Customershares	Dec. 31, 2016USD ($)shares	Jan. 01, 2018USD ($)
Summary Of Significant Accounting Policies [Line Items]
Sales rebates		$ 200,000
Sales rebates on revenue	$ 1,200,000
Performance obligations remaining to be performed	$ 1,060,700,000
Number of customers accounted for more than 10% of accounts receivable | Customer	0	0
Disbursement of pre-funded study costs		$ 138,700,000	$ 150,300,000
Fair value measurements transfers between level 1, level 2, or level 3	$ 0	0	$ 0
Accumulated deficit	(41,487,000)	(120,402,000)
Accounts receivable and unbilled, net	133,449,000	83,079,000
Deferred income tax liability	439,000	560,000
Accrued expenses	87,493,000	23,673,000
Pre-funded study costs	0	57,406,000
Advanced billings	147,935,000	$ 73,756,000
ASC 606
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable and unbilled, net				$ 106,966,000
Pre-funded study costs				0
Advanced billings				112,613,000
ASC 606 | Impact of Adoption of ASC 606 - Adjustments
Summary Of Significant Accounting Policies [Line Items]
Accumulated deficit	2,637,000			5,700,000
Accounts receivable and unbilled, net	(28,729,000)			23,887,000
Deferred income tax liability	2,049,000			(1,600,000)
Accrued expenses	(51,109,000)			35,100,000
Pre-funded study costs	61,156,000			(57,406,000)
Advanced billings	$ (41,732,000)			$ 38,857,000
Stock Options
Summary Of Significant Accounting Policies [Line Items]
Anti-dilutive securities excluded from computation of diluted EPS | shares	121	63	0
Maximum
Summary Of Significant Accounting Policies [Line Items]
Sales rebates			$ 100,000
Estimated useful life of intangible assets	15 years
Maximum | Accounting Standard Update (“ASU”) No. 2016-09
Summary Of Significant Accounting Policies [Line Items]
Discrete Adjustments to Income Tax Expense Benefit		$ 100,000
Maximum | Computer Hardware Software Phone and Medical Imaging Equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of assets	5 years
Maximum | Furniture and Fixtures and Other Equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of assets	7 years
Maximum | Buildings
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of assets	40 years
Maximum | Computer Software Developed Costs
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of assets	3 years
Minimum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of intangible assets	5 years
Minimum | Computer Hardware Software Phone and Medical Imaging Equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of assets	3 years
Minimum | Furniture and Fixtures and Other Equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of assets	5 years
Minimum | Buildings
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of assets	30 years
Miscellaneous Income (Expense), Net
Summary Of Significant Accounting Policies [Line Items]
Net gain (loss) on foreign currency transactions	$ 400,000	(1,000,000)	(700,000)
Selling, General and Administrative
Summary Of Significant Accounting Policies [Line Items]
Advertisement expenses	$ 800,000	$ 600,000	$ 600,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Reconciliation of Denominators and Additional Shares that are Excluded from the Calculation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Weighted-average shares:
Basic weighted-average common shares outstanding									35,547	39,056	35,690
Total weighted-average shares									35,689	39,146	35,778
Earnings per common share—Basic
Net income	$ 22,761	$ 19,305	$ 16,568	$ 14,551	$ 11,291	$ 9,831	$ 9,553	$ 8,447	$ 73,185	$ 39,122	$ 13,425
Net income available to common shareholders—Basic									$ 72,894	$ 39,032	$ 13,392
Net income per common share—Basic	$ 0.64	$ 0.54	$ 0.46	$ 0.41	$ 0.30	$ 0.25	$ 0.24	$ 0.21	$ 2.05	$ 1	$ 0.38
Basic weighted-average common shares outstanding									35,547	39,056	35,690
Effect of diluted shares									1,365	783	639
Diluted weighted-average shares outstanding									36,912	39,839	36,329
Net income per common share—Diluted	$ 0.61	$ 0.52	$ 0.45	$ 0.40	$ 0.30	$ 0.25	$ 0.23	$ 0.20	$ 1.97	$ 0.98	$ 0.37
RSAs
Weighted-average shares:
Basic weighted-average common shares outstanding									142	90	88
Earnings per common share—Basic
Less: Undistributed earnings allocated to RSAs									$ 291	$ 90	$ 33
Basic weighted-average common shares outstanding									142	90	88
Common Stock
Weighted-average shares:
Basic weighted-average common shares outstanding									35,547	39,056	35,690
Earnings per common share—Basic
Basic weighted-average common shares outstanding									35,547	39,056	35,690

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of Impact of Adoption of Accounting Standards (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018	Dec. 31, 2015
Revenue:
Total revenue	$ 192,115	$ 179,253	$ 170,144	$ 163,077	$ 112,682	$ 110,643	$ 106,216	$ 106,611	$ 704,589	$ 436,152	$ 421,582
Operating expenses:
Direct service costs, excluding depreciation and amortization									252,284	211,773	198,510
Reimbursed out-of-pocket expenses									236,775	49,690	50,961
Total direct costs	131,133	123,996	116,676	117,254	68,803	65,106	63,619	63,935	489,059	261,463	249,471
Total operating expenses									603,541	371,294	369,092
Income from operations	30,666	26,918	23,345	20,119	15,437	17,198	16,279	15,944	101,048	64,858	52,490
Income before income taxes									93,951	56,945	21,957
Income tax provision									20,766	17,823	8,532
Net income	$ 22,761	$ 19,305	$ 16,568	$ 14,551	$ 11,291	$ 9,831	$ 9,553	$ 8,447	$ 73,185	$ 39,122	$ 13,425
Net income per share attributable to common shareholders:
Basic	$ 0.64	$ 0.54	$ 0.46	$ 0.41	$ 0.30	$ 0.25	$ 0.24	$ 0.21	$ 2.05	$ 1	$ 0.38
Diluted	$ 0.61	$ 0.52	$ 0.45	$ 0.40	$ 0.30	$ 0.25	$ 0.23	$ 0.20	$ 1.97	$ 0.98	$ 0.37
Weighted average common shares outstanding:
Basic									35,547	39,056	35,690
Diluted									36,912	39,839	36,329
Current assets:
Accounts receivable and unbilled, net	$ 133,449				$ 83,079				$ 133,449	$ 83,079
Prepaid expenses and other current assets	21,383				20,400				21,383	20,400
Total current assets	178,114				129,971				178,114	129,971
Deferred income taxes	713				6,343				713	6,343
Total assets	967,933				950,717				967,933	950,717
Current liabilities:
Accrued expenses	87,493				23,673				87,493	23,673
Pre-funded study costs	0				57,406				0	57,406
Advanced billings	147,935				73,756				147,935	73,756
Other current liabilities	4,861				4,697				4,861	4,697
Total current liabilities	257,026				192,706				257,026	192,706
Deferred income tax liability	439				560				439	560
Other long-term liabilities	12,804				10,740				12,804	10,740
Total liabilities	378,230				447,187				378,230	447,187
Shareholders’ equity:
Accumulated deficit	(41,487)				(120,402)				(41,487)	(120,402)
Total shareholders’ equity	589,703				503,530				589,703	503,530	$ 610,710		$ 413,474
Total liabilities and shareholders’ equity	967,933				$ 950,717				967,933	950,717
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income									73,185	39,122	13,425
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income tax provision (benefit)									3,942	3,237	(9,006)
Changes in assets and liabilities:
Accounts receivable and unbilled, net									(27,047)	(2,898)	(13,727)
Prepaid expenses and other current assets									(1,241)	(3,533)	(3,661)
Accrued expenses									29,029	(1,313)	4,516
Pre-funded study costs									0	5,292	5,400
Advanced billings									35,593	7,735	14,723
Other assets and liabilities, net									1,925	2,782	(841)
Net cash provided by operating activities									156,584	97,385	91,732
Revenue Net
Revenue:
Total revenue									704,589	0	0
Direct Service Revenue
Revenue:
Total revenue									0	386,462	370,621
Reimbursed Out-of-Pocket Revenue
Revenue:
Total revenue									0	$ 49,690	$ 50,961
ASC 606
Current assets:
Accounts receivable and unbilled, net												$ 106,966
Current liabilities:
Pre-funded study costs												0
Advanced billings												112,613
ASC 606 | Impact of Adoption of ASC 606 - Adjustments
Revenue:
Total revenue									(155,221)
Operating expenses:
Direct service costs, excluding depreciation and amortization									0
Reimbursed out-of-pocket expenses									(165,470)
Total direct costs									(165,470)
Total operating expenses									(165,470)
Income from operations									10,249
Income before income taxes									10,249
Income tax provision									1,882
Net income									$ 8,367
Net income per share attributable to common shareholders:
Basic									$ 0.24
Diluted									$ 0.23
Weighted average common shares outstanding:
Basic									0
Diluted									0
Current assets:
Accounts receivable and unbilled, net	(28,729)								$ (28,729)			23,887
Prepaid expenses and other current assets	1,147								1,147
Total current assets	(27,582)								(27,582)
Deferred income taxes	(389)								(389)
Total assets	(27,971)								(27,971)
Current liabilities:
Accrued expenses	(51,109)								(51,109)			35,100
Pre-funded study costs	61,156								61,156			(57,406)
Advanced billings	(41,732)								(41,732)			38,857
Other current liabilities	(590)								(590)
Total current liabilities	(32,275)								(32,275)
Deferred income tax liability	2,049								2,049			(1,600)
Other long-term liabilities	(382)								(382)
Total liabilities	(30,608)								(30,608)
Shareholders’ equity:
Accumulated deficit	2,637								2,637			$ 5,700
Total shareholders’ equity	2,637								2,637
Total liabilities and shareholders’ equity	(27,971)								(27,971)
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income									8,367
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income tax provision (benefit)									4,002
Changes in assets and liabilities:
Accounts receivable and unbilled, net									4,842
Prepaid expenses and other current assets									(1,147)
Accrued expenses									(15,967)
Pre-funded study costs									3,782
Advanced billings									(2,907)
Other assets and liabilities, net									(972)
Net cash provided by operating activities									0
ASC 606 | Impact of Adoption of ASC 606 - Adjustments | Revenue Net
Revenue:
Total revenue									(704,589)
ASC 606 | Impact of Adoption of ASC 606 - Adjustments | Direct Service Revenue
Revenue:
Total revenue									478,063
ASC 606 | Impact of Adoption of ASC 606 - Adjustments | Reimbursed Out-of-Pocket Revenue
Revenue:
Total revenue									71,305
ASC 606 | Impact of Adoption of ASC 606 - As Revised under ASC 605
Revenue:
Total revenue									549,368
Operating expenses:
Direct service costs, excluding depreciation and amortization									252,284
Reimbursed out-of-pocket expenses									71,305
Total direct costs									323,589
Total operating expenses									438,071
Income from operations									111,297
Income before income taxes									104,200
Income tax provision									22,648
Net income									$ 81,552
Net income per share attributable to common shareholders:
Basic									$ 2.29
Diluted									$ 2.20
Weighted average common shares outstanding:
Basic									35,547
Diluted									36,912
Current assets:
Accounts receivable and unbilled, net	104,720								$ 104,720
Prepaid expenses and other current assets	22,530								22,530
Total current assets	150,532								150,532
Deferred income taxes	324								324
Total assets	939,962								939,962
Current liabilities:
Accrued expenses	36,384								36,384
Pre-funded study costs	61,156								61,156
Advanced billings	106,203								106,203
Other current liabilities	4,271								4,271
Total current liabilities	224,751								224,751
Deferred income tax liability	2,488								2,488
Other long-term liabilities	12,422								12,422
Total liabilities	347,622								347,622
Shareholders’ equity:
Accumulated deficit	(38,850)								(38,850)
Total shareholders’ equity	592,340								592,340
Total liabilities and shareholders’ equity	$ 939,962								939,962
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income									81,552
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income tax provision (benefit)									7,944
Changes in assets and liabilities:
Accounts receivable and unbilled, net									(22,205)
Prepaid expenses and other current assets									(2,388)
Accrued expenses									13,062
Pre-funded study costs									3,782
Advanced billings									32,686
Other assets and liabilities, net									953
Net cash provided by operating activities									156,584
ASC 606 | Impact of Adoption of ASC 606 - As Revised under ASC 605 | Revenue Net
Revenue:
Total revenue									0
ASC 606 | Impact of Adoption of ASC 606 - As Revised under ASC 605 | Direct Service Revenue
Revenue:
Total revenue									478,063
ASC 606 | Impact of Adoption of ASC 606 - As Revised under ASC 605 | Reimbursed Out-of-Pocket Revenue
Revenue:
Total revenue									$ 71,305

Contract Assets and Contract _3

Contract Assets and Contract Liabilities - Summary of Accounts Receivable and Unbilled, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 13, 2016	Dec. 31, 2015
Contract With Customer Asset And Liability [Line Items]
Accounts receivable	$ 85,120		$ 55,599
Unbilled receivables	49,361		28,153
Less: allowance for doubtful accounts	(1,032)		(673)	$ (3,222)	$ (3,222)	$ (1,724)
Total accounts receivable and unbilled, net	133,449		$ 83,079
ASC 606
Contract With Customer Asset And Liability [Line Items]
Accounts receivable		$ 70,943
Unbilled receivables		36,696
Less: allowance for doubtful accounts		(673)
Total accounts receivable and unbilled, net		106,966
ASC 606 | Impact of Adoption of ASC 606 - Adjustments
Contract With Customer Asset And Liability [Line Items]
Accounts receivable		15,344
Unbilled receivables		8,543
Total accounts receivable and unbilled, net	$ (28,729)	$ 23,887

Contract Assets and Contract _4

Contract Assets and Contract Liabilities - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Contract With Customer Asset And Liability [Line Items]
Unbilled receivables	$ 49,361		$ 28,153
Advanced billings	147,935		$ 73,756
ASC 606
Contract With Customer Asset And Liability [Line Items]
Unbilled receivables		$ 36,696
Advanced billings		112,613
ASC 606 | Impact of Adoption of ASC 606 - Adjustments
Contract With Customer Asset And Liability [Line Items]
Unbilled receivables		8,543
Advanced billings	$ (41,732)	$ 38,857

Contract Assets and Contract _5

Contract Assets and Contract Liabilities - Summary of Advanced Bllings (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Contract With Customer Asset And Liability [Line Items]
Advanced billings	$ 147,935		$ 73,756
Pre-funded study costs	0		$ 57,406
ASC 606
Contract With Customer Asset And Liability [Line Items]
Advanced billings		$ 112,613
Pre-funded study costs		0
ASC 606 | Impact of Adoption of ASC 606 - Adjustments
Contract With Customer Asset And Liability [Line Items]
Advanced billings	(41,732)	38,857
Pre-funded study costs	$ 61,156	$ (57,406)

Contract Assets and Contract _6

Contract Assets and Contract Liabilities - Schedule of Allowance for Doubtful Account Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue From Contract With Customer [Abstract]
Allowance for doubtful accounts - beginning balance	$ (673)	$ (3,222)	$ (1,724)
Current year provision	(791)	(250)	(2,166)
Write-offs, recoveries and the effects of foreign currency exchange	432	2,799	668
Allowance for doubtful accounts - ending balance	$ (1,032)	$ (673)	$ (3,222)

Property and Equipment, Net - S

Property and Equipment, Net - Summary of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property Plant and Equipment [Line Items]
Property and equipment at cost	$ 85,366	$ 74,859
Less: Accumulated depreciation	(33,111)	(26,120)
Property and equipment, net	52,255	48,739
Land
Property Plant and Equipment [Line Items]
Property and equipment at cost	1,240	972
Equipment
Property Plant and Equipment [Line Items]
Property and equipment at cost	15,437	12,171
Furniture, fixtures, and leasehold improvements
Property Plant and Equipment [Line Items]
Property and equipment at cost	20,892	21,280
Computer hardware, software, and phone equipment
Property Plant and Equipment [Line Items]
Property and equipment at cost	11,566	9,571
Buildings
Property Plant and Equipment [Line Items]
Property and equipment at cost	8,145	2,559
Deemed assets from landlord building construction
Property Plant and Equipment [Line Items]
Property and equipment at cost	22,752	22,752
Construction-in-Progress
Property Plant and Equipment [Line Items]
Property and equipment at cost	$ 5,334	$ 5,554

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2011AgreementRenewalOption
Property Plant And Equipment [Abstract]
Depreciation | $	$ 9,240	$ 8,574	$ 7,442
Number of lease agreements | Agreement				2
Lease occupancy year				2,012
Lease expiration year				2,027
Number of lease renewal, 10-year option | RenewalOption				1
Lease term upon renewal				10 years
Term of lease	15 years

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Goodwill And Intangible Assets [Line Items]
Fair value assets measured on non-recurring basis	$ 967,933	$ 950,717
Goodwill	660,981	$ 660,981
Accumulated goodwill impairment losses to date	9,300
Fair Value Measurement Non-Recurring | Level 3
Goodwill And Intangible Assets [Line Items]
Fair value assets measured on non-recurring basis	692,600
Goodwill	661,000
Indefinite-lived intangible assets	$ 31,600

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Schedule of Intangible Assets, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-lived intangible assets:
Total finite-lived intangible assets	$ 275,230	$ 275,230
Accumulated amortization:
Total accumulated amortization	(237,697)	(208,136)
Total finite-lived intangible assets, net	37,533	67,094
Trade name (indefinite-lived)	31,646	31,646
Total intangible assets, net	69,179	98,740
Backlog
Finite-lived intangible assets:
Total finite-lived intangible assets	72,630	72,630
Accumulated amortization:
Total accumulated amortization	(72,630)	(72,630)
Customer Relationships
Finite-lived intangible assets:
Total finite-lived intangible assets	145,051	145,051
Accumulated amortization:
Total accumulated amortization	(110,636)	(92,661)
Developed Technologies
Finite-lived intangible assets:
Total finite-lived intangible assets	54,475	54,475
Accumulated amortization:
Total accumulated amortization	(51,751)	(40,856)
Other
Finite-lived intangible assets:
Total finite-lived intangible assets	3,074	3,074
Accumulated amortization:
Total accumulated amortization	$ (2,680)	$ (1,989)

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Schedule of Estimated Amortization Expense of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
2,019	$ 14,829
2,020	7,876
2,021	5,114
2,022	3,353
2,023	2,199
Later years	4,162
Total finite-lived intangible assets, net	$ 37,533	$ 67,094

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accrued Liabilities And Other Liabilities [Abstract]
Employee compensation and benefits	$ 31,344	$ 19,707
Project related reimbursable expenses	51,109	0
Other	5,040	3,966
Total accrued expenses	$ 87,493	$ 23,673

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Debt	$ 80,438
Less unamortized discount	(282)	$ (399)
Less current portion of long-term debt	0	(16,500)
Long-term debt, net, less current portion	79,721	205,111
Revolving credit facility
Debt Instrument [Line Items]
Debt		70,000
Term loan
Debt Instrument [Line Items]
Debt	80,438	152,625
Less unamortized term loan debt issuance costs	$ (435)	$ (615)

Debt - Schedule of Principal Pa

Debt - Schedule of Principal Payments on Debt Due (Details) $ in Thousands	Dec. 31, 2018USD ($)
Debt Disclosure [Abstract]
2,019	$ 0
2,020	0
2,021	80,438
Total	$ 80,438

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($)	Dec. 08, 2016	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Outstanding borrowings			$ 80,438,000
Unamortized issue discount			282,000	$ 399,000
Cash and cash equivalents			23,275,000	26,485,000
Loss on extinguishment of debt			$ 0	0	$ 10,726,000
Senior Secured Revolving Credit Facility
Debt Instrument [Line Items]
Outstanding borrowings				70,000,000
Senior Secured Credit Agreement
Debt Instrument [Line Items]
Description of variable interest rate basis			Borrowings under the Senior Secured Credit Facilities bear interest at a rate equal to, at our option, either (i) the adjusted Eurocurrency rate based on LIBOR for U.S. dollar deposits for loans denominated in dollars, EURIBOR for Euro deposits for loans denominated in Euros and the offer rate for any other currencies for loans denominated in such other currencies for the relevant interest period plus an applicable margin from 1.25% to 2.25% based on the total net leverage ratio from less than 1.50:1.00 to greater than 3.75:1:00, or (ii) an alternative base rate (determined by reference to the highest of (a) the prime commercial lending rate of the administrative agent, as established from time to time, (b) the Federal Funds Rate plus 0.50% and (c) the one-month adjusted Eurocurrency rate for loans in U.S. dollars plus 1.00%) plus an applicable margin from 0.25% to 1.25% based on the total net leverage ratio from less than 1.50:1.00 to greater than 3.75:1:00.  The applicable margin as of December 31, 2018 was 1.25% for eurocurrency loans and 0.25% for base rate loans.
Ratio of consolidated funded indebtedness to consolidated EBITDA			4
Loss on extinguishment of debt					10,700,000
Debt instrument, third party fees					500,000
Debt instrument unamortized loan origination fee					$ 10,200,000
Senior Secured Credit Agreement | Eurocurrency Rate
Debt Instrument [Line Items]
Applicable margin on variable rate			1.25%
Senior Secured Credit Agreement | Federal Funds Rate
Debt Instrument [Line Items]
Applicable margin on variable rate			0.50%
Senior Secured Credit Agreement | One-Month Adjusted Eurocurrency Rate
Debt Instrument [Line Items]
Applicable margin on variable rate			1.00%
Senior Secured Credit Agreement | Base Rate
Debt Instrument [Line Items]
Applicable margin on variable rate			0.25%
Senior Secured Credit Agreement | Minimum | Eurocurrency Rate
Debt Instrument [Line Items]
Applicable margin on variable rate			1.25%
Debt instrument, total net leverage ratio			3.75
Senior Secured Credit Agreement | Minimum | Base Rate
Debt Instrument [Line Items]
Applicable margin on variable rate			0.25%
Debt instrument, total net leverage ratio			3.75
Senior Secured Credit Agreement | Maximum
Debt Instrument [Line Items]
Ratio of consolidated funded indebtedness to consolidated EBITDA			4.50
Cash consideration			$ 25,000,000
Ratio of consolidated EBITDA to consolidated interest expense			3
Senior Secured Credit Agreement | Maximum | Unrestricted
Debt Instrument [Line Items]
Cash and cash equivalents			$ 50,000,000
Senior Secured Credit Agreement | Maximum | Foreign | Unrestricted
Debt Instrument [Line Items]
Cash and cash equivalents			$ 25,000,000
Senior Secured Credit Agreement | Maximum | Eurocurrency Rate
Debt Instrument [Line Items]
Applicable margin on variable rate			2.25%
Debt instrument, total net leverage ratio			1.50
Senior Secured Credit Agreement | Maximum | Base Rate
Debt Instrument [Line Items]
Applicable margin on variable rate			1.25%
Debt instrument, total net leverage ratio			1.50
Senior Secured Credit Agreement | Senior Secured Term Loan Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 165,000,000
Debt instrument percentage of face value issued	99.70%
Expiration date	2021-12
Unamortized issue discount	$ 500,000		$ 300,000	400,000
Origination fees	800,000		$ 400,000	600,000
Senior Secured Credit Agreement | Term Loan
Debt Instrument [Line Items]
Interest rate applicable			3.77%
Senior Secured Credit Agreement | Senior Secured Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 150,000,000
Expiration date	2021-12
Commitment fee percentage		0.375%
Total net leverage ratio limit to determine commitment fee			3
Outstanding borrowings			$ 0	70,000,000
Undrawn capacity			149,800,000	80,000,000
Outstanding letters of credit			200,000	300,000
Origination fees	$ 1,600,000		$ 900,000	$ 1,300,000
Senior Secured Credit Agreement | Senior Secured Revolving Credit Facility | Senior Secured Credit Facilities Bear Interest - Scenario 1
Debt Instrument [Line Items]
Commitment fee percentage			0.50%
Senior Secured Credit Agreement | Senior Secured Revolving Credit Facility | Senior Secured Credit Facilities Bear Interest - Scenario 2
Debt Instrument [Line Items]
Commitment fee percentage			0.375%
Senior Secured Credit Agreement | Senior Secured Revolving Credit Facility | Eurocurrency Rate
Debt Instrument [Line Items]
Interest rate applicable			3.77%

Commitments, Contingencies, a_3

Commitments, Contingencies, and Guarantees - Schedule of Minimum Future Lease Payments (Details) $ in Thousands	Dec. 31, 2018USD ($)
Operating Leased Assets [Line Items]
Operating Leases, 2019	$ 8,173
Operating Leases, 2020	13,460
Operating Leases, 2021	12,837
Operating Leases, 2022	10,451
Operating Leases, 2023	8,486
Operating Leases, Thereafter	109,622
Operating Leases, Total minimum lease payments	163,029
Non-Related Party
Operating Leased Assets [Line Items]
Operating Leases, 2019	6,186
Operating Leases, 2020	6,617
Operating Leases, 2021	5,873
Operating Leases, 2022	3,694
Operating Leases, 2023	3,257
Operating Leases, Thereafter	5,752
Operating Leases, Total minimum lease payments	31,379
Related Party
Operating Leased Assets [Line Items]
Operating Leases, 2019	1,987
Operating Leases, 2020	6,843
Operating Leases, 2021	6,964
Operating Leases, 2022	6,757
Operating Leases, 2023	5,229
Operating Leases, Thereafter	103,870
Operating Leases, Total minimum lease payments	$ 131,650

Commitments, Contingencies, a_4

Commitments, Contingencies, and Guarantees - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments And Contingencies Disclosure [Abstract]
Operating leases rental expense total	$ 9,200,000	$ 7,900,000	$ 6,700,000
Minimum purchase commitments for project related supplies	$ 5,200,000
Minimum purchase commitments, description	The Company has several minimum purchase commitments for project related supplies totaling $5.2 million. In return for the commitment, Medpace receives preferential pricing. The commitments expire at various times through 2023.

Commitments, Contingencies, a_5

Commitments, Contingencies, and Guarantees - Schedule of Minimum Annual Payments Required in Conjunction with Landlord Liability (Details) - Deemed Landlord Liabilities $ in Thousands	Dec. 31, 2018USD ($)
Commitments Contingencies And Guarantees [Line Items]
Related Party Minimum Lease Payments, 2019	$ 3,918
Related Party Minimum Lease Payments, 2020	3,988
Related Party Minimum Lease Payments, 2021	4,039
Related Party Minimum Lease Payments, 2022	4,092
Related Party Minimum Lease Payments, 2023	4,145
Related Party Minimum Lease Payments, Thereafter	15,697
Related Party Minimum Lease Payments, Total	35,879
Related Party Minimum Lease Payments, Interest, 2019	1,818
Related Party Minimum Lease Payments, Interest, 2020	1,662
Related Party Minimum Lease Payments, Interest, 2021	1,490
Related Party Minimum Lease Payments, Interest, 2022	1,301
Related Party Minimum Lease Payments, Interest, 2023	1,095
Related Party Minimum Lease Payments, Interest, Thereafter	1,929
Related Party Minimum Lease Payments, Interest, Total	9,295
Total Principal Amounts Due, 2019	2,100
Total Principal Amounts Due, 2020	2,326
Total Principal Amounts Due, 2021	2,549
Total Principal Amounts Due, 2022	2,791
Total Principal Amounts Due, 2023	3,050
Total Principal Amounts Due, Thereafter	13,768
Total Principal Amounts Due, Total	$ 26,584

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Details)	12 Months Ended
	Dec. 31, 2018USD ($)shares	Dec. 31, 2017USD ($)shares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)employeeshares	Aug. 11, 2016shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted	584,301	853,896	683,001
Share-based payment award description				If Medpace Investors exercised the call right, it could do so up to the later of twelve months following the employee’s departure date or six months following the determination that the former employee was directly or indirectly engaged in competitive business activities
Incremental stock based compensation expense | $			$ 3,100,000
Stock-based compensation expense | $	$ 6,499,000	$ 4,463,000	9,815,000
Stock-based compensation liability associated with modified stock options reclassified to additional paid in capital | $			10,500,000
Stock-based compensation liability | $	0	0
Actual tax benefits recognized related to stock-based compensation | $	$ 1,000,000	$ 500,000	$ 1,000,000
Vesting Equally on Second, Third and Fourth Anniversary of Grant Date Over Four Years
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted		15,000
Award vesting period		4 years
RSA Modification
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested restricted stock awards held by employees				688,599
Number of current employees holding unvested restricted stock | employee				158
Incremental stock based compensation expense | $				$ 0
Stock-based compensation expense | $				$ 5,700,000
Restricted Shares (RSAs and RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares granted	300,200	156,000	11,111
Unvested restricted stock awards held by employees	421,200	183,629	59,258	90,697
Shares granted and immediately vested			11,111
2016 Incentive Award Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares registered and available for grant	6,000,000				6,000,000
Awards granted to employees	850,700	968,550
Stock options granted			648,180
Shares available for future stock compensation grants	3,800,000	4,300,000
Plan expiration year	2,026
2016 Incentive Award Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation option terms	10 years
2016 Incentive Award Plan | Non-employee Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted	33,801
Award vesting description	These awards will vest on the earlier of (a) the day immediately preceding the date of the first annual meeting following the date of grant and (b) the first anniversary of the date of grant, subject to the non-employee director continuing in service through the applicable vesting date.
2016 Incentive Award Plan | Vesting on October 31, 2016 and Eight equal monthly Installments
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted			21,530
Award vesting description	stock options with various vesting schedules, but all of which vest within a calendar year of the respective grant date
2016 Incentive Award Plan | Vesting Over One Year | Non-employee Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted		41,346
Award vesting period		1 year
2016 Incentive Award Plan | Stock Options | Vesting After Four Years
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted	550,500	797,550	626,650
Award vesting period	4 years	4 years	4 years
2016 Incentive Award Plan | Restricted Stock Awards (RSA) | Vesting After Four Years
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		4 years
Shares granted		118,000
2016 Incentive Award Plan | Restricted Stock Units (RSU) | Vesting After Four Years
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period	4 years	4 years
Shares granted	300,200	38,000
2014 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation option terms	7 years
Stock options granted			45,932
2014 Equity Incentive Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period	4 years
2014 Equity Incentive Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period	3 years
2014 Equity Incentive Plan | Vesting Equally Over Four Years
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted			34,821
Award vesting period			4 years
2014 Equity Incentive Plan | Fully Vested Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares granted			11,111

Shareholders' Equity -Schedule

Shareholders' Equity -Schedule of Weighted-Average Assumptions Used in BSM Model to Calculate Fair Value of Options (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions And Methodology [Abstract]
Expected holding period - years	5 years 4 months 24 days	5 years 4 months 24 days	3 years 7 months 6 days
Expected volatility	27.00%	28.00%	30.20%
Risk-free interest rate	2.80%	2.00%	1.00%
Expected dividend yield	0.00%	0.00%	0.00%

Shareholders' Equity - Schedule

Shareholders' Equity - Schedule of Grant Date Fair Value and Stock-based Compensation Expense Allocated (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 6,499	$ 4,463	$ 9,815
Stock Options
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Weighted average, grant date fair value	$ 11.51	$ 8.54	$ 6.91
Restricted Shares (RSAs and RSUs)
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Weighted average, grant date fair value	$ 49.38	$ 31.90	$ 15.08
Total Direct Costs
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 4,132	$ 2,128	$ 5,555
Selling, General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 2,367	$ 2,335	$ 4,260

Shareholders' Equity - Schedu_2

Shareholders' Equity - Schedule of Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity [Abstract]
Number of Options, Outstanding - beginning of Period	2,782,868	2,350,166	1,794,709
Number of Options, Granted	584,301	853,896	683,001
Number of Options, Exercised	(169,771)	(116,787)	(36,980)
Number of Options, Forfeited/Expired	(252,358)	(304,407)	(90,564)
Number of Options, Outstanding - end of period	2,945,040	2,782,868	2,350,166
Number of Options, Exercisable - end of period	1,096,116	917,592	647,343
Weighted Average Exercise Price, Outstanding - beginning of Period	$ 20.73	$ 17.57	$ 15.42
Weighted Average Exercise Price, Granted	37.72	28.67	22.80
Weighted Average Exercise Price, Exercised	14.98	15.52	14.50
Weighted Average Exercise Price, Forfeited/Expired	23.69	20.55	15.85
Weighted Average Exercise Price, Outstanding - end of period	24.18	20.73	17.57
Weighted Average Exercise Price, Exercisable - end of period	$ 16.01	$ 15.40	$ 15.22

Shareholders' Equity - Schedu_3

Shareholders' Equity - Schedule of Restricted Share Activity (Details) - Restricted Shares (RSAs and RSUs) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding and unvested - beginning of period	183,629	59,258	90,697
Granted	300,200	156,000	11,111
Vested	(29,629)	(29,629)	(41,069)
Forfeited	(33,000)	(2,000)	(1,481)
Outstanding and unvested - end of period	421,200	183,629	59,258
Cumulative vested shares - end of period	1,913,916	1,884,287	1,854,658

Shareholders' Equity - Schedu_4

Shareholders' Equity - Schedule of Stock Options Expected To Vest, Stock Options Exercisable, and Unvested Restricted Share Awards Expected To Vest (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted Average Exercise Price, Number of stock options expected to vest	$ 24.18
Weighted Average Exercise Price, Total stock options exercisable - December 31, 2018	$ 16.01	$ 15.40	$ 15.22
Number of stock options expected to vest	2,945,040
Number of Restricted Shares expected to vest	421,200
Weighted Average Remaining Life (Years), Number of stock options expected to vest	4 years 4 months 24 days
Weighted Average Remaining Life (Years), Total stock options exercisable - December 31, 2018	3 years
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of stock options expected to vest	2,945,040
Total stock options exercisable - December 31, 2018	1,096,116
Unrecognized compensation cost - December 31, 2018	$ 10,021
Weighted average years over which unrecognized compensation cost will be recognized	2 years 8 months 12 days
RSAs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average years over which unrecognized compensation cost will be recognized	3 years 6 months
Number of Restricted Shares expected to vest	421,200
Unrecognized compensation cost - December 31, 2018	$ 15,734

Shareholder's Equity - Schedule

Shareholder's Equity - Schedule of Aggregate Intrinsic Value of Stock Options Exercised, Fair Values of Awards Vested, and Share Based Liabilities Settled (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total intrinsic value of stock options exercised	$ 5,326	$ 1,619	$ 403
Total grant-date fair value of stock options vested	1,417	1,317	1,384
Total share-based liabilities settled	0	0	76
Restricted Shares (RSAs and RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total grant-date fair value of restricted shares vested	447	447	614
Total settlement date fair value of restricted shares vested	$ 1,568	$ 1,074	$ 1,236

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Contribution Plan Disclosure [Line Items]
Plan name	401(k) plan
Maximum annual contribution by employee, percentage of pre-tax earnings	50.00%
U.S. Employees
Defined Contribution Plan Disclosure [Line Items]
Recognized cost of employee benefit plan	$ 2.7	$ 2.3	$ 2
Minimum period of service required for matching contribution eligibility	1 year
Minimum required period of service for employer contributions to fully vest	3 years
Non-U.S. Employees | Defined Contribution Arrangements
Defined Contribution Plan Disclosure [Line Items]
Recognized cost of employee benefit plan	$ 1	$ 0.9	$ 0.7

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	1 Months Ended	12 Months Ended			24 Months Ended
	May 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018
Income Tax Disclosure [Line Items]
U.S. federal corporate tax rate		21.00%	35.00%	35.00%
Tax Cuts and Jobs Act of 2017, accounting complete true or false		true
Transition tax expense		$ 126,000	$ 574,000	$ 0
Final transition tax liability		$ 700,000			$ 700,000
Percentage of transition tax liability impact on effective tax rate		0.10%	1.00%	0.00%
Provisional tax benefit			$ 3,400,000
Final tax benefit		$ 195,000	$ 3,418,000	$ 0	3,600,000
Percentage of tax benefit from adjustment of deferred tax assets and liabilities		0.20%	6.00%	0.00%
Deferred tax liability not recognized from undistributed earnings of foreign subsidiaries		$ 0			0
Deduction for dividends received in tax reform act		100.00%
Dividends received from owned foreign corporations by us corporate shareholders		10.00%
Foreign corporations shareholders holding period		1 year
Amount of undistributed earnings of foreign subsidiaries for which deferred foreign withholding taxes not recorded		$ 21,100,000			21,100,000
Deferred tax assets, foreign operating loss carryforwards		248,000	$ 246,000		248,000
Deferred tax assets, valuation allowance		$ 169,000	2,394,000		169,000
Percentage of foreign net operating loss carryforward		59.00%
Deferred tax assets			21,100,000
Deferred tax liabilities			100,000
Liability for interest and penalties		$ 1,000,000	1,400,000		1,000,000
Liability for uncertain tax position		$ 7,200,000	$ 5,900,000		7,200,000
Number of tax years		4 years
IRC Section 382 Ownership Shift
Income Tax Disclosure [Line Items]
Disposal of deferred tax assets		$ 7,400,000
Reduction in deferred credit		6,900,000
Net increase in tax expense		$ 500,000
NephroGenex, Inc.
Income Tax Disclosure [Line Items]
Deferred tax assets	$ 22,200,000
Tax effected net operating losses	13,500,000
Tax effected capitalized research and development expenses	8,500,000
Tax effected federal tax credits	200,000
Deferred tax liabilities	$ 100,000
Minimum
Income Tax Disclosure [Line Items]
Foreign net operating loss carryforwards expiration year		2,020
Maximum
Income Tax Disclosure [Line Items]
Foreign net operating loss carryforwards expiration year		2,027
U.S. State and Local
Income Tax Disclosure [Line Items]
Tax credits carryforward expiration year		2,023
Foreign Tax Authority
Income Tax Disclosure [Line Items]
Deferred tax assets, valuation allowance		$ 200,000			$ 200,000
Foreign, State and Local Jurisdictions | Earliest Tax Year
Income Tax Disclosure [Line Items]
Open tax year		2,014
Foreign, State and Local Jurisdictions | Latest Tax Year
Income Tax Disclosure [Line Items]
Open tax year		2,018
Federal | Earliest Tax Year
Income Tax Disclosure [Line Items]
Open tax year		2,015
Federal | Latest Tax Year
Income Tax Disclosure [Line Items]
Open tax year		2,018

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Domestic	$ 88,014	$ 52,986	$ 18,016
Foreign jurisdictions	5,937	3,959	3,941
Income before income taxes	$ 93,951	$ 56,945	$ 21,957

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments [Abstract]
U.S. Federal, Current	$ 13,372	$ 10,953	$ 15,105
U.S. Federal, Deferred	4,172	3,466	(8,784)
U.S. Federal, Total	17,544	14,419	6,321
U.S. state and local, Current	1,912	2,032	1,636
U.S. state and local, Deferred	(116)	51	(524)
U.S. state and local, Total	1,796	2,083	1,112
Foreign jurisdictions, Current	1,408	1,576	710
Foreign jurisdictions, Deferred	18	(255)	389
Foreign jurisdictions, Total	1,426	1,321	1,099
Income tax provision (benefit), Current	16,692	14,561	17,451
Income tax provision (benefit), Deferred	4,074	3,262	(8,919)
Income tax provision (benefit), Total	$ 20,766	$ 17,823	$ 8,532

Income Taxes - Summary Of Diffe

Income Taxes - Summary Of Difference Between Statutory Rate for Federal Income Tax and Effective Income Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended			24 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income tax expense calculated at the federal statutory rate	$ 19,730	$ 19,931	$ 7,685
State and local taxes, net of federal benefit	1,978	1,606	912
Tax on foreign earnings, net of tax credits and deductions	172	(69)	(26)
Tax reform adjustment	(195)	(3,418)	0	$ (3,600)
Write off of Deferred Tax Assets	509	0	0
Deferred credit	(802)	(1,053)	0
Change in valuation allowance	0	0	0
Stock-based awards	(651)	(179)	(534)
Tax reform adjustment	126	574	0
Other	687	483	174
State/Local tax credits	(1,253)	(1,187)	(1,049)
Foreign tax credits	(727)	0	0
Change in liability for uncertain tax positions	1,102	1,141	1,212
Other	90	(6)	158
Income tax provision (benefit), Total	$ 20,766	$ 17,823	$ 8,532
Income tax expense calculated at the federal statutory rate	21.00%	35.00%	35.00%
State and local taxes, net of federal benefit	2.10%	2.80%	4.20%
Tax on foreign earnings, net of tax credits and deductions	0.20%	(0.10%)	(0.10%)
Tax reform adjustment	(0.20%)	(6.00%)	0.00%
Write off of Deferred Tax Assets	0.60%	0.00%	0.00%
Deferred credit	(0.90%)	(1.90%)	0.00%
Change in valuation allowance	0.00%	0.00%	0.00%
Stock-based awards	(0.70%)	(0.30%)	(2.40%)
Tax reform adjustment	0.10%	1.00%	0.00%
Other	0.70%	0.90%	0.80%
State/Local tax credits	(1.30%)	(2.10%)	(4.80%)
Foreign tax credits	(0.80%)	0.00%	0.00%
Change in liability for uncertain tax positions	1.20%	2.00%	5.50%
Other	0.10%	0.00%	0.70%
Effective Income Tax Rate Reconciliation, Percent	22.10%	31.30%	38.90%

Income Taxes - Schedule of Co_2

Income Taxes - Schedule of Components of Company's Net Deferred Tax Asset (Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Accrued liabilities	$ 18,670	$ 17,563
Depreciation and amortization	872	980
Foreign operating loss carryforward	248	246
U.S. federal tax credits and carryforward	0	8,152
U.S. state and local tax credits and carryforward	223	1,799
Other	41	667
Valuation allowance	(169)	(2,394)
Total deferred tax assets	19,885	27,013
Deferred tax liabilities:
Depreciation and amortization	(18,803)	(20,117)
Prepaid expenses	(550)	(572)
Other	(258)	(541)
Total deferred tax liabilities	(19,611)	(21,230)
Net deferred tax asset	$ 274	$ 5,783

Income Taxes - Schedule of Annu

Income Taxes - Schedule of Annual Activity Related to Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Beginning Balance	$ 2,394	$ 987	$ 1,021
Additions charged to expense	0	0	0
Additions due to asset acquisition	0	2,033	0
Reductions from utilization, reassessments and expirations	(2,225)	3	(34)
Remeasurement due to effect of tax reform	0	(629)	0
Ending Balance	$ 169	$ 2,394	$ 987

Income Taxes - Schedule of Gros

Income Taxes - Schedule of Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Beginning balance	$ 6,890	$ 5,698	$ 2,604
Increases in tax positions for prior years	0	5	0
Decreases in tax positions for prior years	(579)	0	(196)
Increases in tax positions for current year	2,214	1,187	3,365
Lapse in statute of limitations	0	0	(75)
Ending Balance	$ 8,525	$ 6,890	$ 5,698

Miscellaneous Income (Expense_3

Miscellaneous Income (Expense), Net - Components of Miscellaneous Income (Expense), Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Income And Expenses [Abstract]
Net gain (loss) on foreign-currency transactions	$ 386	$ (1,004)	$ (660)
Other income	674	650	237
Miscellaneous income (expense), net	$ 1,060	$ (354)	$ (423)

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details)	Jan. 11, 2017USD ($)	Sep. 30, 2018Director	Jun. 30, 2017USD ($)	Dec. 31, 2018USD ($)AgreementRenewalOptionBuilding	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)Parcel	Dec. 31, 2011AgreementRenewalOption	Dec. 31, 2012USD ($)
Related Party Transaction [Line Items]
Accounts receivable and unbilled, net				$ 3,800,000	$ 1,000,000
Advanced billings				$ 400,000	1,700,000
Pre-funded study costs with related parties					1,000,000
Number of lease renewal, 10-year option | RenewalOption							1
Lease expiration year							2,027
Number of lease agreements | Agreement							2
Lease occupancy year							2,012
Lease term upon renewal							10 years
Term of lease				15 years
Deemed landlord liability, long-term portions				$ 24,484,000	26,602,000
Accounts payable includes related parties				300,000	200,000
Cinven
Related Party Transaction [Line Items]
Members of board of directors resigned as result of remaining shares of common stock sold | Director		3
Management fees expense with related party						$ 200,000
Director fees with related party				100,000	100,000
Cinven | Maximum
Related Party Transaction [Line Items]
Travel expenses with related party				100,000	100,000	100,000
Medpace Investors
Related Party Transaction [Line Items]
Related party tax expense						800,000
Repayments of Related Party Debt						300,000
Proceeds from Related Party Debt						300,000
Employee Loans | Prepaid Expenses and Other Current Assets and Other Assets
Related Party Transaction [Line Items]
Employee advances receivables				$ 200,000	200,000
Service Agreements | Coherus Bio Sciences Inc
Related Party Transaction [Line Items]
Amount of investment								$ 2,500,000
Service agreement cancellation notice period				30 days
Revenue with related parties					8,000,000	22,300,000
Reimbursed out-of-pocket revenue with related parties					1,300,000	5,100,000
Reimbursed out-of-pocket expenses with related parties					1,300,000	5,100,000
Accounts receivable and unbilled, net					300,000
Advanced billings					1,500,000
Pre-funded study costs with related parties					1,000,000
Service Agreements | Xenon
Related Party Transaction [Line Items]
Revenue with related parties			$ 600,000			1,300,000
Reimbursed out-of-pocket revenue with related parties			100,000			200,000
Reimbursed out-of-pocket expenses with related parties			$ 100,000			200,000
Service Agreements | Cymabay
Related Party Transaction [Line Items]
Revenue with related parties					600,000	300,000
Accounts receivable and unbilled, net				$ 2,500,000	100,000
Service Agreements | Cymabay | Revenue Net
Related Party Transaction [Line Items]
Revenue with related parties				10,800,000
Service Agreements | LIB
Related Party Transaction [Line Items]
Revenue with related parties					1,400,000	$ 200,000
Accounts receivable and unbilled, net				1,000,000	500,000
Advanced billings				300,000	200,000
Service Agreements | LIB | Revenue Net
Related Party Transaction [Line Items]
Revenue with related parties				3,700,000
Service Agreements | CinRx Pharma and Subsidiaries
Related Party Transaction [Line Items]
Revenue with related parties					400,000
Accounts receivable and unbilled, net				400,000
Service Agreements | CinRx Pharma and Subsidiaries | Revenue Net
Related Party Transaction [Line Items]
Revenue with related parties				500,000
Service Agreements | The Summit
Related Party Transaction [Line Items]
Expenses incurred				$ 400,000
Purchase of Real Estate Properties | Chief Executive Officer
Related Party Transaction [Line Items]
Number of parcel in real estate property | Parcel						4
Purchase price of real estate property	$ 400,000
Transaction closed date	Jan. 11, 2017
Leased Real Estate
Related Party Transaction [Line Items]
Number of lease renewal, 10-year option | RenewalOption				2
Lease term upon renewal				10 years
Lease expiration year				2,040
Leased Real Estate | Chief Executive Officer
Related Party Transaction [Line Items]
Term of lease				12 years
Lease expiration period				2022-11
Number of lease renewal, 10-year option | RenewalOption				1
Lease term upon renewal				10 years
Annual base rent				$ 2,200,000
Lease expense recognized				$ 2,200,000	2,100,000	$ 2,100,000
Storage space lease basis				month to month basis
Leased Real Estate | Chief Executive Officer And Immediate Family
Related Party Transaction [Line Items]
Number of lease renewal, 10-year option | RenewalOption				1
Lease expiration year				2,027
Number of lease agreements | Agreement				2
Number of buildings | Building				2
Lease occupancy year				2,012
Lease term upon renewal				10 years
Term of lease				15 years
Related party capital lease payments				$ 3,800,000	3,800,000	3,700,000
Deemed landlord liability, current				2,100,000	1,900,000
Deemed landlord liability, long-term portions				24,500,000	26,600,000
Leased Real Estate | Property and Equipment, Net | Chief Executive Officer And Immediate Family | Building
Related Party Transaction [Line Items]
Deemed assets, net				14,600,000	16,300,000
Travel Services | Chief Executive Officer
Related Party Transaction [Line Items]
Travel expenses with related party				1,300,000	1,100,000	$ 1,000,000
Accounts payable includes related parties				$ 200,000	$ 200,000

Cash Flow Statement - Supplem_2

Cash Flow Statement - Supplemental Information - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Supplemental Cash Flow Information [Abstract]
Acquisition of net assets	$ 0.7
Deferred tax assets, net	21.1
Deferred tax liabilities, net	0.1
Deferred credits	20.3
Accounts receivable and unbilled, net	0.6
Other assets	$ 0.1

Entity Wide Disclosures - Addit

Entity Wide Disclosures - Additional Information (Details) - U.S. - Geographical Locations	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Total Revenue
Product And Services Information [Line Items]
Percentage of total revenue and service revenue to consolidated total revenue and service revenue	97.00%
Service Revenue, Net
Product And Services Information [Line Items]
Percentage of total revenue and service revenue to consolidated total revenue and service revenue		98.00%

Entity Wide Disclosures - Summa

Entity Wide Disclosures - Summary of Property and Equipment, Net by Geographic Region (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property and equipment, net:
Property and equipment, net	$ 52,255	$ 48,739
U.S.
Property and equipment, net:
Property and equipment, net	38,609	37,535
Europe, Belgium
Property and equipment, net:
Property and equipment, net	6,014	4,132
Europe, Other
Property and equipment, net:
Property and equipment, net	5,500	5,134
Europe
Property and equipment, net:
Property and equipment, net	11,514	9,266
Other
Property and equipment, net:
Property and equipment, net	$ 2,132	$ 1,938

Entity Wide Disclosures - Sum_2

Entity Wide Disclosures - Summary of Revenue by Major Source (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation Of Revenue [Line Items]
Total revenue	$ 192,115	$ 179,253	$ 170,144	$ 163,077	$ 112,682	$ 110,643	$ 106,216	$ 106,611	$ 704,589	$ 436,152	$ 421,582
Oncology
Disaggregation Of Revenue [Line Items]
Total revenue									189,026
Other
Disaggregation Of Revenue [Line Items]
Total revenue									161,194
Metabolic
Disaggregation Of Revenue [Line Items]
Total revenue									94,128
Cardiology
Disaggregation Of Revenue [Line Items]
Total revenue									91,824
AVAI
Disaggregation Of Revenue [Line Items]
Total revenue									76,739
Central Nervous System
Disaggregation Of Revenue [Line Items]
Total revenue									53,904
Endocrine
Disaggregation Of Revenue [Line Items]
Total revenue									26,002
Medical Devices
Disaggregation Of Revenue [Line Items]
Total revenue									11,772
Revenue Net
Disaggregation Of Revenue [Line Items]
Total revenue									$ 704,589	$ 0	$ 0

Quarterly Financial Data (Una_3

Quarterly Financial Data (Unaudited) - Schedule of Unaudited Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Total revenue	$ 192,115	$ 179,253	$ 170,144	$ 163,077	$ 112,682	$ 110,643	$ 106,216	$ 106,611	$ 704,589	$ 436,152	$ 421,582
Total direct costs	131,133	123,996	116,676	117,254	68,803	65,106	63,619	63,935	489,059	261,463	249,471
Income from operations	30,666	26,918	23,345	20,119	15,437	17,198	16,279	15,944	101,048	64,858	52,490
Net income	$ 22,761	$ 19,305	$ 16,568	$ 14,551	$ 11,291	$ 9,831	$ 9,553	$ 8,447	$ 73,185	$ 39,122	$ 13,425
Net income per common share—Basic	$ 0.64	$ 0.54	$ 0.46	$ 0.41	$ 0.30	$ 0.25	$ 0.24	$ 0.21	$ 2.05	$ 1	$ 0.38
Net income per common share—Diluted	$ 0.61	$ 0.52	$ 0.45	$ 0.40	$ 0.30	$ 0.25	$ 0.23	$ 0.20	$ 1.97	$ 0.98	$ 0.37