Acquisitions (Details) (USD $)	12 Months Ended			0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013	Dec. 01, 2014	Aug. 16, 2013
Business Acquisition [Line Items]
Goodwill acquired	$ 135,890,000	$ 7,034,000	$ 4,998,000
Reduction in tax valuation allowance, tax benefit recorded	2,200,000	3,100,000	10,100,000
RPD Business
Business Acquisition [Line Items]
Cash paid for acquisition				200,000
Value of common stock issued for acquisition				114,100,000
Goodwill acquired				129,406,000
Revenue recognized since acquisition date	2,900,000
Net losses since acquisition date	(4,300,000)
Net tangible assets acquired				134,613,000
RPD Business | Common Stock
Business Acquisition [Line Items]
Common stock used to pay for acquisition, shares				1,526,790
RPD Business | Minimum
Business Acquisition [Line Items]
Discount rate				13.50%
RPD Business | Maximum
Business Acquisition [Line Items]
Discount rate				15.60%
RPD Business | Selling, general and administrative expenses
Business Acquisition [Line Items]
Acquisition and transition costs	4,400,000
Amortization of intangibles	200,000
iTVX, Inc.
Business Acquisition [Line Items]
Cash paid for acquisition					383,000
Goodwill acquired					1,900,000
Revenue recognized since acquisition date	1,300,000	700,000
Net losses since acquisition date	1,500,000	900,000
Name of acquired entity					iTVX
Description of acquired entity					provider of branded entertainment analytics, insight and research
Total purchase price as of acquisition date					2,800,000
Initial consideration transferred					800,000
Consideration transferred, value of common shares					405,000
Contingent consideration earnout period in years					2 years
Contingent consideration percentage of payment paid in cash					25.00%
Contingent consideration percentage of payment paid in stock					75.00%
Contingent consideration fixed stock price					$ 21.795
Intangible assets					900,000
Net tangible assets acquired					300,000
Deferred tax liabilities acquired					300,000
Reduction in tax valuation allowance, tax benefit recorded	(300,000)
iTVX, Inc. | Common Stock
Business Acquisition [Line Items]
Common stock used to pay for acquisition, shares					17,209
iTVX, Inc. | Minimum
Business Acquisition [Line Items]
Acquired intangible assets, useful life	1 year
iTVX, Inc. | Maximum
Business Acquisition [Line Items]
Acquired intangible assets, useful life	6 years
iTVX, Inc. | Selling, general and administrative expenses
Business Acquisition [Line Items]
Amortization of intangibles	200,000	100,000
Acquisition costs	0	200,000
iTVX, Inc. | Fair Value, Inputs, Level 3
Business Acquisition [Line Items]
Undiscounted amount of contingent consideration, range of outcomes, low					500,000
Undiscounted amount of contingent consideration, range of outcomes, high					7,000,000
Contingent consideration liability	4,500,000	4,700,000			2,000,000
iTVX, Inc. | Fair Value, Inputs, Level 3 | Selling, general and administrative expenses
Business Acquisition [Line Items]
Fair value remeasurement of contingent consideration liability	(200,000)	2,700,000
Accrued compensation | iTVX, Inc. | Fair Value, Inputs, Level 3
Business Acquisition [Line Items]
Contingent consideration liability	4,500,000
WPP Luxembourg | RPD Business
Business Acquisition [Line Items]
Proceeds from stock purchase agreement				55,800,000
Goodwill acquired				$ 20,300,000
WPP Luxembourg | RPD Business | Common Stock
Business Acquisition [Line Items]
Common stock issued for stock purchase agreement (shares)				943,834