Stockholders' Equity Share-based Compensation Plans Activity (Details) (USD $)	12 Months Ended			3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013	Jun. 30, 2011 Installment
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock based compensation expense	$ 38,200,000
Unrecognized stock based compensation expense, period for recognition	7 years 2 months
Property and Equipment
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation capitalized as a component of property and equipment	754,000	1,614,000	512,000
2011 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued pursuant to employee stock purchase plan (ESPP)	603,000	506,000	511,000
Shares issued under the Employee Stock Purchase Plan	16,183
2011 Employee Stock Purchase Plan | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued pursuant to employee stock purchase plan (ESPP)	600,000
Weighted average purchase price under the Employee Stock Purchase Plan	$ 37.26
Shares available for grant, Employee Stock Purchase Plan	117,266
Cash received for shares purchased under the Employee Stock Purchase Plan	300,000
Stock Options
Options Outstanding (in shares)
Options, beginning	2,393,565
Granted	5,267
Exercised	(547,526)
Forfeited	(22,000)
Options, ending	1,829,306
Weighted Average Exercise Price (usd per share)
Weighted average exercise price, beginning	$ 20.68
Weighted average exercise price, granted	$ 46.92
Weighted average exercise price, exercised	$ 18.82
Weighted average exercise price, forfeited	$ 22.03
Weighted average exercise price, ending	$ 21.37
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Aggregate intrinsic value of options outstanding	39,100,000
Weighted average remaining contractual term of options outstanding	6 years 1 month
Number of options exercisable	1,142,607
Weighted average exercise price of options exercisable (usd per share)	$ 22.58
Aggregate intrinsic value of options exercisable	25,800,000
Weighted average remaining contractual term of options exercisable	5 years 8 months
Deferred Stock Units (DSUs) | Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year
Awards Outstanding (in shares)
Outstanding, beginning	208,895
Granted	14,917
Vested or issued	(30,581)
Forfeited	0
Outstanding, ending	193,231
Vested but not issued	187,806
Weighted Average Grant Date Fair Value (usd per share)
Weighted average grant date fair value, beginning	$ 16.54
Weighted average grant date fair value, granted	$ 46.92
Weighted average grant date fair value, issued	$ 55.90
Weighted average grant date fair value, forfeited	$ 0.00
Weighted average grant date fair value, ending	$ 18.72
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	5 years
Awards vested in period	80,188	158,628
Shares withheld to pay associated withholding taxes on behalf of employees	38,500	64,590
Awards Outstanding (in shares)
Outstanding, beginning	223,276
Granted	620,883
Vested or issued	(113,693)
Forfeited	(7,360)
Outstanding, ending	723,106.000	223,276
Weighted Average Grant Date Fair Value (usd per share)
Weighted average grant date fair value, beginning	$ 26.78
Weighted average grant date fair value, granted	$ 52.96
Weighted average grant date fair value, issued	$ 53.56
Weighted average grant date fair value, forfeited	$ 38.71
Weighted average grant date fair value, ending	$ 51.20	$ 26.78
Restricted Stock Units (RSUs) | Capitalized software
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation capitalized as a component of property and equipment		19,000
Restricted Stock Units (RSUs) | Research, Technology and Innovation Costs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		30,000
Stock Settled Stock Appreciation Rights
Awards Outstanding (in shares)
Outstanding, beginning	75,000
Granted	0
Vested or issued	0
Forfeited	0
Outstanding, ending	75,000
Weighted Average Grant Date Fair Value (usd per share)
Weighted average grant date fair value, beginning	$ 5.33
Weighted average grant date fair value, granted	$ 0.00
Weighted average grant date fair value, issued	$ 0.00
Weighted average grant date fair value, forfeited	$ 0.00
Weighted average grant date fair value, ending	$ 5.33
Weighted Average Base Price (usd per share)
Weighted average base price, beginning	$ 14.50
Weighted average base price, granted	$ 0.00
Weighted average base price, issued	$ 0.00
Weighted average base price, forfeited	$ 0.00
Weighted average base price, ending	$ 14.50
Stock Options Non Employee | Essentials
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price range, lower limit (usd per share)				$ 17.43
Exercise price range, upper limit (usd per share)				$ 22.20
Non-Employee options, expiration period				10 years
Number of equal vesting installments				4
Options Outstanding (in shares)
Granted				40,000
Stock Options Non Employee | Essentials | Property and Equipment | Capitalized software
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation capitalized as a component of property and equipment	$ 1,000,000	$ 1,100,000
Common Stock | 2011 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)	200,000
Right | Shareholders Rights Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of outstanding common stock required to be acquired for Shareholder's Rights to be effective	15.00%
Percent of outstanding common stock to be included in tender offer for Shareholder's Rights to be effective	15.00%
Redemption price per right allowed in absence of acquisition by beneficial owner (usd per share)	$ 0.001