CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (PARENTHETICAL) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense		$ 22,120	$ 16,965	$ 106,089	$ 54,103
Cost of Sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	[1]	3,468	2,270	15,465	6,325
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense		9,881	7,855	37,569	23,623
Selling General And Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense		$ 8,771	$ 6,840	$ 53,055	$ 24,155

[1] During the three and nine months ended December 31, 2016, $2.8 million and $8.3 million, respectively, of share-based compensation expense was capitalized to inventory. The amount of share-based compensation included in cost of sales during the three months ended December 31, 2016 included $3.5 million of previously capitalized share-based compensation expense in inventory that was sold. The amount of share-based compensation included in cost of sales during the nine months ended December 31, 2016 included $11.3 million of previously capitalized share-based compensation expense in inventory that was sold and $4.2 million of share-based compensation expense related to the Company's acquisition of Atmel that was not previously capitalized to inventory. During the three and nine months ended December 31, 2015, $2.0 million and $5.6 million, respectively, of share-based compensation expense was capitalized to inventory and $2.3 million and $6.3 million, respectively, of previously capitalized share-based compensation expense in inventory was sold.