Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Apr. 29, 2016	Mar. 31, 2016
Liabilities:
Warrant liability		$ 5,400
Fair Value, Measurements, Recurring
Assets:
Total assets at fair value	$ 0		$ 0
Liabilities:
Warrant liability	52		0
Total liabilities at fair value	52		0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total assets at fair value	0		0
Liabilities:
Warrant liability	0		0
Total liabilities at fair value	0		0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Total assets at fair value	0		0
Liabilities:
Warrant liability	0		0
Total liabilities at fair value	0		0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Total assets at fair value	0		0
Liabilities:
Warrant liability	52		0
Total liabilities at fair value	$ 52		$ 0