Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Income Tax Contingency [Line Items]
Expenses (benefit) from income taxes	$ 302,000	$ (85,000)	$ 0
Valuation allowance for company	28,800,000	16,900,000
State net operating losses	114,300,000
U.S Federal net operating losses	215,600,000
Stock-based compensation for tax deductions	$ 4,645,000	3,312,000
Federal tax credit carryforwards expire year	2028
Minimum percentage of ownership required to increase in stock of the ownership	5.00%
Ownership change, increase in ownership percentage,term	3 years
Increase in ownership percentage of certain stockholders	50.00%
Accumulated unremitted earnings from foreign subsidiaries	$ 900,000	100,000	33,000
Unrecognized tax benefits that would affect income tax expense	3,500,000
Unrecognized tax benefits	3,489,000	1,826,000	735,000	$ 597,000
Interest and penalties related to uncertain tax positions	$ 0	$ 0	$ 0
U.S. [Member]
Income Tax Contingency [Line Items]
Expiration year	2028
Stock-based compensation for tax deductions	$ 45,300,000
U.S. [Member] | Research and Development [Member]
Income Tax Contingency [Line Items]
Research and development credits	$ 5,900,000
State Tax [Member]
Income Tax Contingency [Line Items]
Expiration year	2025
Stock-based compensation for tax deductions	$ 4,000,000
California [Member] | Research and Development [Member]
Income Tax Contingency [Line Items]
Research and development credits	$ 1,500,000
Oregon [Member]
Income Tax Contingency [Line Items]
Federal tax credit carryforwards expire year	2014
Oregon [Member] | Research and Development [Member]
Income Tax Contingency [Line Items]
Research and development credits	$ 1,200,000