FAIR VALUE MEASUREMENTS - Schedule of Reconciliation of Changes in Fair Value of Level 3 Financial Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Collection of contingently returnable consideration	$ 12,864	$ 9,306	$ 0
Fair value, measurements, recurring | Contingent Purchase Consideration
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	7,293	4,484
Additions to Level 3	(660)
Increase in fair value and accretion expense (included within research and development expense)	(153)	(152)
Increase (Decrease) in fair value		21
Gross presentation of contingently returnable consideration to contingent purchase consideration	(3,910)	(2,636)
Payments made	6,567
Ending balance	5,449	7,293	4,484
Fair value, measurements, recurring | Contingently Returnable Consideration
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	16,131	0
Contingently returnable consideration		19,125
Increase (Decrease) in fair value	(610)	3,676
Gross presentation of contingently returnable consideration to contingent purchase consideration	3,910	2,636
Collection of contingently returnable consideration	(19,431)	(9,306)
Ending balance	$ 0	$ 16,131	$ 0