Revenue Recognition - Financial Statement Impact of Adoption (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Apr. 01, 2018	Mar. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	$ 34,007	$ 33,865
Sales and marketing	4,754	5,130
Accounts receivable, net	20,306		$ 19,513	$ 16,389
Contract assets	5,273		4,583	0
Prepaid expenses and other current assets	5,421		5,097	5,593
Other non-current assets	4,673		4,893	2,484
Contract liabilities	30,781		33,826	26,820
Retained earnings	104,479		106,215	103,601
Net loss	(1,736)	(2,958)
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	34,056
Sales and marketing	4,719
Accounts receivable, net	19,491			16,389
Contract assets	0			0
Prepaid expenses and other current assets	5,890			5,593
Other non-current assets	2,211			2,484
Contract liabilities	25,230			26,820
Retained earnings	101,949			$ 103,601
Net loss	(1,652)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	(49)
Sales and marketing	35
Accounts receivable, net	815		3,124
Contract assets	5,273		4,583
Prepaid expenses and other current assets	(469)		(496)
Other non-current assets	2,462		2,409
Contract liabilities	5,551		7,006
Retained earnings	2,530		$ 2,614
Net loss	(84)
Products
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	9,080	10,283
Products | Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	8,702
Products | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	378
Support, maintenance and subscription services
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	17,929	16,667
Support, maintenance and subscription services | Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	18,187
Support, maintenance and subscription services | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	(258)
Professional services
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	6,998	$ 6,915
Professional services | Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	7,167
Professional services | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	$ (169)