Stockholders' Equity - Common Stock - Additional Information (Detail)			12 Months Ended
	Mar. 26, 2020	Jun. 25, 2019 $ / shares	Mar. 31, 2020 USD ($) TradingDay shares	Mar. 31, 2019 USD ($) shares	Mar. 31, 2018	Aug. 14, 2018 shares	Jul. 31, 2018 shares	Jul. 26, 2018 shares	Mar. 16, 2018 USD ($)	Apr. 24, 2017 shares	Aug. 31, 2015 shares	Aug. 31, 2013 shares	Jan. 31, 2012 shares	May 31, 2008 shares
Class Of Stock [Line Items]
Issuance of common stock from stock options exercises, net, Shares			0	622,192
Issuance of common stock			130,558,098	124,015,429
Common stock, shares authorized			200,000,000	200,000,000
Stock option exercised			0	622,192
Reverse stock split			20:1 to 40:1
Number of minimum consecutive trading days | TradingDay			10
Certificate of Amendment [Member]
Class Of Stock [Line Items]
Common stock, shares authorized								200,000,000
Maximum [Member]
Class Of Stock [Line Items]
Conversion ratio	40
Minimum [Member]
Class Of Stock [Line Items]
Minimum closing bid price | $ / shares		$ 1
Conversion ratio	20
At-The-Market Facility [Member]
Class Of Stock [Line Items]
Issuance of common stock			6,087,382
2018 Sales Agreement [Member]
Class Of Stock [Line Items]
Equity sales agreement expiration date					Feb. 22, 2021
Value of shares sold under equity distribution agreement | $			$ 18,700,000
Issuance of common stock			17,719,185
2018 Sales Agreement [Member] | Maximum [Member]
Class Of Stock [Line Items]
Common stock value reserved for future issuance | $			$ 81,300,000
2018 Sales Agreement [Member] | At-The-Market Facility [Member]
Class Of Stock [Line Items]
Common stock value reserved for future issuance | $			$ 31,300,000
Issuance of common stock from stock options exercises, net, Shares			6,087,382	11,631,803
Value of shares sold under equity distribution agreement | $			$ 5,000,000	$ 13,200,000
2018 Sales Agreement [Member] | At-The-Market Facility [Member] | Maximum [Member]
Class Of Stock [Line Items]
Common stock value reserved for future issuance | $									$ 50,000,000
Equity Incentive Plan 2008 [Member]
Class Of Stock [Line Items]
Common shares authorized to be issued														1,521,584
Termination date of equity incentive plan			Jul. 01, 2018
Shares issued during the year				896,256
Equity Incentive Plan 2012 [Member]
Class Of Stock [Line Items]
Common shares authorized to be issued							11,000,000				6,000,000	5,000,000	6,553,986
Shares available for issuance			14,158,654				28,553,986
Termination period of Equity Incentive Plan			10 years
Inducement Award Agreements [Member]
Class Of Stock [Line Items]
Common shares authorized to be issued						1,135,408				2,297,034