Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common stock	Additional Paid In Capital	Accumulated Other Comprehensive Income (Loss)	Treasury stock	Retained Earnings
Beginning Balance at Mar. 31, 2014	$ 409,161	$ 50	$ 273,574	$ 2,772	$ (117,802)	$ 250,567
Beginning Balance (in shares) at Mar. 31, 2014		49,922,959			8,757,175
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	22,709					22,709
Unrealized net investment gains	21			21
Unrealized net gains on derivative financial instruments	(490)			(490)
Cumulative translation adjustments	(2,107)			(2,107)
Issuance of common stock pursuant to exercise of options	66	$ 0	66
Issuance of common stock pursuant to exercise of options (in shares)		11,850
Issuance of common stock pursuant to vesting of restricted stock units	1	$ 1
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		670,521
Stock-based compensation expense for restricted stock units granted to employees	7,362		7,362
Issuance of common stock under employee stock purchase plan	2,760		2,760
Issuance of common stock under employee stock purchase plan (in shares)		59,897
Repurchase of treasury stock	(30,894)				$ (30,894)
Repurchase of treasury stock (in shares)					726,526
Tax benefits of disqualifying dispositions of incentive stock options	4,033		4,033
Ending Balance at Sep. 30, 2014	412,622	$ 51	287,795	196	$ (148,696)	273,276
Ending Balance (in shares) at Sep. 30, 2014		50,665,227			9,483,701
Beginning Balance at Mar. 31, 2015	435,750	$ 51	298,101	(4,645)	$ (169,516)	311,759
Beginning Balance (in shares) at Mar. 31, 2015		50,812,548			10,004,743
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(246)					(246)
Unrealized net investment gains	58			58
Unrealized net gains on derivative financial instruments	820			820
Cumulative translation adjustments	853			853
Issuance of common stock pursuant to vesting of restricted stock units	1	$ 1
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		463,744
Stock-based compensation expense for restricted stock units granted to employees	11,041		11,041
Issuance of common stock under employee stock purchase plan	$ 3,028		3,028
Issuance of common stock under employee stock purchase plan (in shares)	82,836	82,836
Repurchase of treasury stock	$ (184,995)				$ (184,995)
Repurchase of treasury stock (in shares)					4,722,119
Issuance of shares related to the acquisition of the Communications Business of Danaher	2,305,611	$ 62	2,305,549
Issuance of shares related to the acquisition of the Communication business of Danaher (in shares)		62,499,644
Tax benefits of disqualifying dispositions of incentive stock options	1,699		1,699
Ending Balance at Sep. 30, 2015	$ 2,573,620	$ 114	$ 2,619,418	$ (2,914)	$ (354,511)	$ 311,513
Ending Balance (in shares) at Sep. 30, 2015		113,858,772			14,726,862